Rock Band Drum Versions

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.

If you're talking about your Rock Band 2 save file that contains your bands and your preferences, deleting them won't help because they're so tiny to begin with.

If you mean your Rock Band songs, it might help depending on how many you have. You will always be able to download them again later on without paying again, but it might be a pain as you have to do them all individually.