BJ and I are Wii fans, but we bought the RB games for XBox 360. I don't recall the details, but I believe the Wii cuts out a few features? I think one of them was ability to download songs (important!) but don't quote me on that.

I also prefer the GH peripherals. The drums, at least. We have RB1 drums and they aren't so great. The GH drums are a lot more solid. In either case, be sure you play with your shoes off; the base pedals they come with are a bit flimsy and will be broken by more zealous drummers.

And I don't know what kind of musician you are, but drum skills translate to the game drums pretty well. BJ and his two drummer friends jumped right into hard/expert levels while most of us can barely play easy! Drums are hard!

I personally feel it's worth it for the wireless guitar/bass and a more solid drum set. And absolutely be sure you have a guitar AND a bass unless you are friendless. The Beatles Rock Band set looks pretty sweet.

I also highly recommend Guitar Hero 5. GH1-3 was good before RB came out, GH4 was meh, but GH5 is really good. Good sound track and you can double up on instruments (ex: two people can play guitar instead of one guitar and one bass).

If I were just starting out as a fake-rockstar, I would invest in GH5 and those peripherals, Beatles RB (and one of their special edition guitars, but that's just me fangirling) and LEGO RB (which isn't out yet so I don't know if it's good but they're gonna have LEGO QUEEN!!!). Maybe RB2 if you have the extra money to blow.