The answer? All Xbox 360 guitars are compatible with Rock Band. All of them. Even most third-party controllers should work. However, things aren't quite as rosy for PlayStation 3 owners.

For Xbox 360 owners, both the Guitar Hero 2 X-plorer and wireless Guitar Hero 3 Les Paul (pictured below right) will fill in as extra instruments. PlayStation 2 users have their pick of controllers released to this point, although while Harmonix has stated third-party controllers will work, testing results are scarce at this point.

As for the PlayStation 3, it was once believed that any PS3 Guitar Hero guitar would work. However, IGN reports that the PlayStation 3's wireless Guitar Hero 3 controller, the Les Paul, won't work with Rock Band, at least in its current slate. That puts PS3 owners in a tough spot, as individual Rock Band instruments won't be available until next year and there aren't any other guitars they can use with the game. However, the PS3's wireless Rock Band controller is interoperable with the PS2 version, and vice versa.

On the flip side, Rock Band guitars do not reliably function with Guitar Hero games--publisher RedOctane has been notoriously unfriendly to third-party peripherals with its games--making the Guitar Hero-branded controllers the most compatible between the two franchises. Of course, no Guitar Hero controllers feature the Rock Band effects knob. Feel that headache coming on?

Unfortunately, there really is no ideal solution for Xbox 360 users who wish to continue playing previous Guitar Hero games. The best combination would be a Guitar Hero 3 wireless Les Paul for bass, with a wired Rock Band controller for lead guitar--if the Les Paul wasn't known for having problems with its detachable neck, dropping notes at random in some cases. And the X-plorer is undoubtedly the worst of all 360 guitars, making it an even less attractive option. Hopefully most prospective buyers will already own a guitar, thus freeing themselves of the hard choice.

For more Rock Band info, check out the full Shacknews rundown.