Actually, you may still skip entire acts. I am not sure what the update did in 1.0.2b regarding "...no longer skip entire acts in multiplayer", but nothing stops you from joining a friend's game as long as the game you are joining was created in a difficulty level that you have already unlocked. To date the latest patch is 1.0.5b. To get your friend to nightmare your friend needs to reach level 25. To do this you will just need a little gold to gear up the low level character in the Auction House.
"Rushing" someone in Diablo III is a bit different than it was in Diablo II. I have not found a quick way to accomplish this, but I have managed to shave quite a bit of time off of the process. The process I have been using involves locating the best places to gather experience and skipping mostly all of the quests. Please comment on this post if you can provide further insight.
The places I go to farm experience are:
- A1, The Imprisoned Angel - The Cursed Hold
- A2, A Royal Audience
- A3, Heart of Sin
- A4, Beneath the Spire
When the character being rushed begins gathering experience at any given place the blue items dropping on the ground should be too high level for the char to use. When the char reaches the level where he or she can actually use the blue items which are dropping that is a pretty good indicator that it is time to stop, gear up at the auction house and move to the next act. Another indicator is when the char stops getting good experience.
Auction House Tip - Make sure to get socketed items whenever possible. Also, get items with the character's prime stat, vitality, and + experience. Try and maximize the DPS for the weapons as well. Put rubies in the weapons to increase damage, and dex/prime stat gems in everything else.
Here is a step by step set of more detailed instructions:
- First take a level one char and bring them to about level 5 by playing around in A1.
- When the character gets between level 5 and 10, go to the Auction House and purchase items that have + experience on kill, the character's primary stat and vitality. Make sure to get items with sockets when available. Make sure to get the highest DPS weapon you can find. Place vitality and primary stat gems in any socketed items.
- Start A1 quest, "The Imprisoned Angel, The Cursed Hold". Let the low level character join the game. Run this quest until the low level character stops gaining at least a level every run.
- Start A2 quest, "A Royal Audience". This is one of the best places in the game for levelling. Have the lower level character join. Kill all the snakes in Emperor Hakan's anteroom, then continue killing snakes all the way to the sewers. Try not to destroy the constructs until they have spit out all of the snakes they are going to spit out. When you reach the entrance to the sewers leave the game, change the quest back to "A Royal Audience", and repeat until the low level character is level 18-19.
- Now go to the auction house to gear up the low level char again. Make sure to get + experience items and socketed items when possible.
- Next start the A3 quest, "Heart of Sin". Let the low level character join and run through this quest line to Azmodan until the low level char reaches 22-23.
- It's up to you as to whether or not you make another stop at the Auction house now. Depending on the items you have found you may not need to. Start an Act 4 game, any quest. I like to run from "Beneath the Spire" on, but it's really just a matter of preference. Play A4 and kill Diablo. Keep playing A4 until you reach level 25.
Now then, from here on out:
- Auction House
- A1, The Imprisoned Angel - The Cursed Hold
- Auction House
- A2, A Royal Audience
- Auction House
- A3, Heart of Sin
- Auction House
- A4, Beneath the Spire
...rinse, repeat.
In patch 1.05 the drop rates were doubled and Monster Power added a new bonus.
Using the base numbers from the Blizzard forums:
Max Max
Non-inf Inferno
base MF 100% 200 300 400 475 500 600 625%
normal 0.0036% 0.0072 0.0108 0.0144 0.0180 0.0207 0.0216 0.0252 0.0261%
elite 0.0440% 0.0880 0.1320 0.1760 0.2200 0.2530 0.2640 0.3080 0.3190%
It is now trivial to get 100 MF with paragon levels and NV stacks, so I usually assume the 100MF line as the new baseline. With the 300% cap in place, bonuses from NV and bonuses from MP the new max MF is 475% in Normal, Nightmare and Hell (produced experimentally by hitting the cap in Act 1 Normal Monster Power 10). The shrine does not bump this to 500%. I am uncertain if the upper limit is 625% or 650%, as I cannot get 5 NV stacks in Monster Power 10, Inferno, but if it behaves like Normal then the max is 625%, calculated as max. 300% from equipment + paragon levels + 250% from MP 10 in Inferno + 75% from 5 NV stacks.
Empirically, running between 325 and 375 I've been seeing a legendary or set item about every 4 or 5 hours of game play, using Act 3, Monster Power 3. Most of them stink, but that's another discussion all together. I've also had sessions where I've popped 3 in a matter of an hour at MF 260% MP 3 Inferno. I also see a legendary about every full act run at max MF in Normal (sometimes none but usually 1 maybe 2).
Keep in mind that each monster kill is an independent event. The odds are not cumulative, so killing 50,000 white mobs at 475% MF does not guarantee you a legendary pop (though I'd be somewhat startled if you didn't get one). You still only have a small chance on each individual kill to see a legendary or set pop. People often misinterpret the probability of independent events to think that doing more of the same will increase their odds. The odds on each kills stays the same. What changes is the odds against seeing another consecutive failure. See this question and answer for a mathematical treatment.
So let's look at the odds of seeing a legendary or set pop after repeated mob kills.
So what is this graph saying? Looking at the 100% MF for normal mobs line, it says that after about 3,000 white mob kills there is a roughly 20% chance that you will have seen a legendary pop. On the Elite 625% MF line it says that there is roughly an 80% chance that you will have seen a legendary pop after 500 elite kills. It is very important to note that none of these values ever equal 100%, even at 32000 kills the number is still "very close" to 100% but not quite.
Tracking these curves it is very clear that even for large numbers of kills the probability of seeing a legendary pop can be very low for normal mobs regardless of MF, but that it is much better to hunt elites for even less than 1,000 elite kills at any MF. It is for this reason that most serious legendary farmers are getting their 5 NV stacks and killing as many elite packs as they can find, not lingering about with white hordes.
So does this match up with the assertion that you kill 10-30 times the whites is as good as killing elites? Looking at the 60% probability line, at 100% MF against elites, if you are killing 10 times then that's better than the 100% MF against white mobs, it's acutally on par with 300% MF against whites. If you are killing 30 times then the 100% MF normal line is actually above the elite line. My battle net account shows that overall, including levelling at all difficulties I am averaging about 20 whites : 1 elite, just as an arbitrary number for consideration. As a level 60 I target elites, so I suspect this ratio is decreasing but it will take some time for all the levelling to be averaged out.
The maximum pop chance from a white mob at maximum MF is still about half of the base chance for an elite. This fits with my empirical experience. I have popped legendaries off white mobs but far more off concentrated attacks on elite packs.
One thing that changes the scenario somewhat, that I've failed to make note of in this answer is that an elite kill gives multiple pops many (not all) of which have a chance of being legendary. Normal kills only give 1 or 2 chances. As both NV and MP add extra items into kills. If we assume that an elite gives twice as many items as a normal (an easy assumption) then with my white:elite ratio we should only use the 10x comparison, and then clearly the elite killing strategy is modestly better. If we make assumptions about 5 NV stacks or higher MP levels then this gap widens.
It is very clear there are diminishing returns for adding MF. The distance between the lines shows there is a large gain for going from 100 to 300 MF, a smaller but decent gain between 300 and 475 MF but a very minuscule gain for pushing to 625%.
If there are hidden mechanics working behind the scenes or if the base rate is incorrect, then this picture will evolve with time.
Best Answer
UPDATED:
Legendaries can drop at any time, anywhere, albeit rarely. With the Loot 2.0 updates, new heroes from lvl 1-59 will get a guaranteed legendary drop for the first kill of The Butcher, Belial, Azmodan and Diablo.
Characters below level 11 are unlikely to find Legendary items, because they have a minimum level requirement. Currently there are no Legendary items available below level 11. (source)
For level 60 characters, you should get a guaranteed legendary drop from Diablo every time you kill him after resetting all of your quests and working your way back to him.
Higher tiers of Torment supposedly include an increase in legendary drop rates, but the exact amount of the bonus has not been disclosed. It doesn't seem to be major, though, so you should pick a lower tier of Torment over a higher one if you will kill significantly faster in the lower tier.
Note, however, that some legendaries will only drop in Torment I - VI.
Original answer:
Yes, there are set and legendary items.
Many of them will be available through crafting, requiring the recipe to drop.
Others will drop randomly, but extremely rarely. This can happen at any level, as not all legendaries are high level gear.
The best legendaries will be Inferno drops.
However, it has been stated that the very best items in the game will not be the set items or legendaries. Instead, the very best will be Inferno level randomly-generated rares.