It seems Minamimoto's is the best solution. Last year I bought Rock Band 2 Special Edition (bundle with one guitar, one mic and one set of drums) for $99 on GameStop, but they don't seem to be making that deal at the moment (at least not online). On Amazon, it's $113. The Beatles instruments are prettier, so I think this set is worth the extra buck.
As for the other instruments, consider getting Lips. At $30, they come with 2 wireless microphones.
Harmonix is only selling one Rock Band 3 bundle, with the keyboard controller, so I guess you don't have much of a choice there. And it's sold out at Amazon, which is even worse.
As for the cymbals, both RB2 cymbals and the new Pro Cymbals are being sold by the same price, $40. The only issue is that the new Cymbals will only be released on October 30th. According to a review, the new cymbals are much superior, so it might be worth the wait.
The only thing missing is the guitar. There are several options. You could pick a RB2 Wireless Guitar for $60, not much to go wrong there. With $20 more, you could get the Beatles Guitar, which could be nice if you get the rest of the set. If you prefer the Guitar Hero controller, it would be the cheapest option, at $50. And, for $70, you can get the Guitar Hero: Warriors of Rock guitar bundle.
You'll be spending at least $360 on all this stuff. But your parties are never gonna be the same. :-)
EDIT: Ah, and if you want to crank it up to eleven, get this setup.
The Wii has had access to the Rock Band store since the release of Rock Band 2. Your Wii needs to be connected to the Internet, and you need regular Wii points in order to purchase the songs. The usual price is 200 points per song, but there are some priced at 100 points.
Also, due to the lack of a hard drive, you will want a good sized SD card in the Wii in order to store the songs. I have a 2GB in mine, but that is because Rock Band 2 does not support a larger card, even though the Wii does. My guess is that Rock Band 3 will support larger SD cards.
Best Answer
If you pick vocals, enable no fail, and turn on Performance Mode in the modifiers menu, then you should just see the background menu.
What performance mode does is take away the HUD and just shows the background video, but it still scores you which is why No Fail is necessary. I'm not sure if doing poorly on vocals will do anything to the sound of the actual vocals. You may want to turn off the crowd noises since the crowd will start booing, though.