That is the resolution of my monitor Before answering, it is important to know what CPU you have. If I suggest a card too powerful, the CPU is going to bottleneck.
I'll just go ahead and assume you are using a Quad Core Core i5 2xxx or Core i7 2600 series.
If that is the case, you won't have problems with CPU bottlenecking, especially when using an unlocked CPU like the 2500k or 2600k.
(Just read you filled in your system specs)
In that case, the best card you can get is a GTX580 1.5GB. That might be a bit expensive for you tough.
Other choices would be a GTX480 (if you can still find one on sale) with an Arctic Cooling Accelero Extreme Plus (normally sold separately, altough one brand sold the cards with this cooler).
You can also go for the GTX570, but try choosing one with a revamped VRM power delivery system, as the stock one is weak for the work it has to do (especially if you consider overclocking).
On the AMD side, the best price performance is the HD6950 2GB.
EDIT: just read your second post. Yes, definitely, if you want to play those games (speaking from experience), you will want a card with more than 1GB of VRAM, pick one of the those I suggested above.
EDIT 2: Oh, you're cool with medium / high with those games (Metro 2033 even has Very High, and a new Metro game is coming too), then a GTX560ti or HD6870 will do.Edited by tpi2007 - 8/6/11 at 8:50am