Hi, I'm a Canon user but before you stone me to death I would recommend you stay with Nikon and buy the best model you can find to take advantage of Nikon's CLS system.
Have a look at Joe McNally's videos on the Nikon (US) website to see examples of the creative lighting system handling difficult lighting situations beautifully.
My 2 cents, I'll go back to planet Canon now. ;-)
Two Jack Studio