YES! ... very decent ... I know it is alot more money, but stretch for a 5850, if at all possible.
You may wish to consider an AMD "Black Quad" and spend your savings on the 5850.
I never did get your exact rendering software requirements or any info on "how much of that" you do.
... Do you already have some experience with that render sw? ... Do you already know how long it takes to do "your-type" of renders, on any system spec?
I just want to make sure we don't shave your budget in the wrong spot, or to spend too much on the wrong component(s). (The 860 may VERY well be complete overkill and the 5770 is likely not rated, for hard-core hi-rez "frames/sec" type games.
this is what i use. feel free to browse the site..well the 860 would be a future proof maybe.. im not a hard core hi rez gamer. i play games like spiderman wos,nfs shift, not playing crysis. im playing crysis 2 on my 360. soo my pc would be on games like starcraft 2. and for some video encoding. that would make my 860 useful.