Hi Micky . The Nikon cash back deal is really good. If it wasn't for Nancy wanting a bridge camera ( she finds the D90 too heavy) I would be thinking on getting another 7000.
Nikon speed lights are in a class of there own , I don't foresee an you won't have any problems with it.The SB 600 would be a perfect combination for a 7000, either wired or in commander mode, and you are getting it at a great price. Regards ... Graham