I've been comparing the 960T with the 975BE and 980BE... I think I'm gonna end up going with the 980BE here http://www.newegg.com/Product/Product.aspx?Item=N82E16819103935
I'm pretty sure I can use my current heatsink/fan on it, but I'll definitely be watching temps to make sure. I can always invest in an aftermarket cooler.
I don't think I need more RAM. 4GB is plenty unless you're doing heavy multitasking or running CAD software or something.
I'll probably think about a new GPU as my next purchase. The 6870 looks pretty nice. Would that be a huge step up from my 4850, you think?