If you get a PS3, you have to get new guitars. Found that out the hard way. You can get the games for PS2, and your liking of each games will depend on how many songs you like between 1,2,3, and Rocks the 80s (I think those are available for PS2).
If you get a PS3, screw Guitar Hero and get Rock Band. More expensive, but also a lot more fun.
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