*double posted*

I haven't ever owned a GH game, but my friends and I usually play GHII on my friends PS2. Seeings that I only own a wii right now I WAS going to get GHIII, but if it's true that there is no quick-play co-op then I won't get it.

I don't think that's true...I think you guys are getting facts wrong somewhere.

Even if it is, that means that you'd need to unlock the songs to play in co-op...which you needed to do in GH1 and 2 as well with single player.

If you wanted to play Free Bird in multiplayer, one of the last songs in GH2, you needed to beat that song in career mode in single player mode first...sounds like it's the same in GH3. You could just do it all on easy or medium to plow through them though...

Even if you need to play co-op career mode to unlock songs, that's no biggie for me...my friends and I play a lot of GH hehe.

RB for me (I play the drums, so it's a no brainer)

I guess you're asking because money is a concern, but Guitar Hero 3 is only $30 cheaper if you are starting from scratch and only buy the game and 1 guitar.  Of course, then you are only another $50 from getting the drums and mic included in the special edition.  If you can afford it, Rock Band is going to be better imo because of more downloadable songs (thanks to MTV license), the original GH developer, Harmonix, and the drums are just like the real instrument when you get to expert. 

Also, you can use the mic and either play drums or guitar to play "co-op" by yourself.  That's a nice feature.

However, if you buy Rock Band you might as well get the Guitar Hero 3 bundle as well because then you'll have 2 guitars, drums, a mic, and both games!  That's $260, though, heh.