First off, nearly every champion can solo top with the right masteries/runes and first item.
The first item has to bring you sustain, it really depends on your champion but usually recommended:
Ranged AD - Life steal! Either Doran's blade or (better - vampiric scepter)
Non ranged - Regrowth pendent > Philosophers stone
AP ranged - Regrowth pendent > Philosophers stone
I understand those items are really generic, but if you play defensively they can keep you in lane indefinitely.
As for champions, some are obviously better than others, and as already mentioned, sustain is THE main thing you need, along with an ability to help you last hit.
Do NOT pick a champ that can be ignored at a tower
So Leona, although tanky, isn't really an option because her damage is so ignorable. Same applies to champions like Soraka etc.
Recommended top lane champs for me are:
- Irelia - very tanky, hard to gank, in built sustain through life
steal, especially post level 6
- Trundle - passive gives sustain, great anti gank + gank aiding skill
- Nidalee - really excels top, heal, big poke nuke, hard to gank post 6, hard to harass
- Swain - Hard CC, great sustain post level 6, hard to harass
- Vlad - Great sustain, very hard to gank, hard to harass
- Warwick - Great sustain, harassing is futile, nice lane to gank post 6.
- Singed - Good farming and sustain with the right set up
- Gangplank - Amazing farming, free cleanse, nice harass, global ult
- Pantheon - Great farming, can help gank mid quickly, hard to tower dive
- Shen - Quite weak at the moment, but global ult makes him a great top
- Jarvan - Similar to irelia with a little less sutain. Very hard to gank, dangerous when getting ganked
- Anivia / Annie - amazing farmers, nasty CC, nice harass, hard to harass
- Gragas - sustain from heal, nice harass, hard to gank
- Maokai - great sustain from passive, needs mana regen to effectively harass, great farmer
- Blitz - dangerous grabs under tower, hard to tower dive, good lane to gank.
- Yorick - good harass, built in life steal, hard CC (slow) for over extended enemies (good lane to gank)
- Galio - good harass, good farm, hard to tower dive (post level 6), good lane to gank (post level 6)
- Orianna - Low mana costs if you just use Q, good harass and farm, hard to harass due to large zoning skill, good lane to gank (post level 6).
I think I covered most of the good solo tops, but to be honest it falls down to either tanky champs who can handle the harass and are hard to push out of lane, damage dealers with life steal that are hard to harass or casters with inbuilt sustain.
I played a lot of ranked, almost 1600 elo atm so I'll try to answer. In order of importance, here is what I think goes into the picks:
1.Role
Each person on your team should have a role. You don't want to pick multiple champions that can only jungle or only mid/top. Unless you've agreed with your team pregame, usually you have 2 bottom, 1 jungle, 1 mid, 1 top. Pick champions for available roles.
2.Counterpicking
In a lot of organized teams and high elo games, people usually pick ad carries or support champions first, since these are generally hard to counter because of the role they play. The ad farms and the support provides utility, roles that's difficult to counter. Mind you, there are specifics like sivir being good against Caitlin.
For the rest of your lanes, you have to be very careful about counterpicking. This is why it is always a bad idea to first pick kassadin, as he has numerous counters that simply prevent him from laning at all.
A lot of people also pick champions that can fill multiple roles to throw people off. For example, when I pick gangplank, he can go top or jungle. If my opponents pick pantheon, gp's hard counter, I go jungle and have a teammate pick another top.
3.Team composition
You have to pay attention to how your team can work together and work to win team fights. Picking for roles and counters do little if your team doesnt work. I'll list the most common team comps:
A. Poke team
Your team has the ability to do significant damage from a distance over time. This allows you to slowly push down towers or seize objectives.
B. Standard team with moderate CC
Basically you have some crowd control abilities that allow you to protect your carries and shut down the enemy team.
C. Gank team
Your team has a lot of mobility and always maintains map presence. Good examples of gank teams include heavy ganking junglers like alistar or champions that can pressure globally like shen, karthus, or twisted fate.
There are many more, experiment!
Best Answer
This depends on your champion and Playstyle. While for most AP based characters his statement is true, it doesn't apply to all AD characters.
The main reason why Penetration stats are strong against Low-Resistance opponents is (as you have already mentioned in your question) because of the "True Damage". Obviously you won't really deal true damage to an enemy (or at least not often) but Armor or Magic penetration will increase your Damage output significantly if you are playing a spell based champion.
Most spell based champions do scale heavily with spell-level rather than with AP/AD. Obviously there are some exceptions to it but as long as you don't have a 0.8 scaling + on at least 2 spells spell levels are stronger than flat AP/AD.
Because of that buying flat penetration like found on Brutalizer or Haunting Guise is exceptionally effective for harrassment during early and even mid-game. It allows you to snowball and while flat Penetration isn't uber strong late-game it's still decent and certainly not wasted.
The biggest disadvantage to it is that lasthitting might get a lot harder since flat AD/AP is the stat to go with there. However if you are comfortable with your lasthitting skills you can safely go for Armor/Magic Penetration early for more aggression in lane.
Please Note that this is really only an advantage on Casters. Autoattack (Ashe/Jinx) or extremely high scaling characters (Zilean/Anivia) are usually stronger with more of their Flat damage stat.