What to upgrade? Gaming preference

[FabienO]

I'm fairly into my PC games, and with Battlefield 3 and Modern Warefare 3 on the way, I'm wondering what I should bump up to help me get some good performance.

My current spec

BenQ G2420HDBL 24" Widescreen LED Monitor
Samsung SyncMaster 2443bw 24" LCD Monitor

Corsair HX 850W ATX Modular SLI Compliant Power Supply
Intel i7 920 @ 4ghz
GB X58A-UD3R
XFX HD Radeon 5870
OCZ Vertex 2E Bigfoot
1TB Seagate Barracuda
Asus Xonar D1 7.1 PCI Sound Card

I was thinking about either selling the 5870 and getting a newer model or perhaps even crossfire. Or selling the Vertex 2E and bumping up to the Vertex 3.

 

[FabienO]

If I were to get a new card, what would I be going for? 5870s in MM go for about £120. None there at present.

I'd sell my 5870 and pay the additional to get good enough card that won't be bottlenecked by my system. Also the vertex 2E -> 3 would mean ~£100 for the Vertex 2E. Then £100 of my own to go up to the 3.