Which guitar are you getting? If it's ever in your future to get drums, the RB2 drums are the way to go. They work in GH5/BH but not GH:WT (Smash Hits and Van Halen are based on WT). All guitars work with GH5 onwards and RB2 onwards.
The RB2 drums are around $50 everywhere now, and $40 at Fry's.
It might be cheaper all around to get one of the special value rb2 kits depending on if any of your places has the deal.