As far as gaming goes you won't notice a difference with any i7 cpu. Your resolution is very gpu taxing so your cpu should last you through even your next gpu upgrade (assuming you use 8x/8x or better sli and you don't skip the next generation), especially if you push it to 4ghz.
I'm not sure how cpu intensive your other tasks are. Maybe someone else can shed some light for you there, but for gaming you are A-OK.
Tbh if money isn't a problem i'd have the latest and greatest (to an extent) at all times.