Depends on the console.
If 360, Rock Band. Better instruments, Harmonix is better to deal with if you need to replace them. You'll be able to add 3 cymbals to the drum set as well. If you're wondering, they charted the song twice in GHWT. Once with 5 notes, another with 4.
If Wii, then Guitar Hero World tour. The GHWT guitar MIGHT work with Rock Band 2 (the GH3 Les Paul will). Don't know about the drum set though. Wii users will have to choose one and stick with it unless you have the money to buy both. But if you do, you're better off buying a 360 and then buying a band set of 1 game and then the other game alone.
If PS3, get the Rock Band drums b/c GHWT's don't work on RB or RB2. All of the GH guitars work with all games. The RB and RB2 guitars work with everything but GH3 and GH3A.