the 9800gtx is a great card, at least you made a good choice. there will be a bottleneck their so maybe you could have gone with a cheaper card, but i remember sumone posting that article about bottlenecks, and that they dont matter, but i never actually read it so not sure wat is was about. At least if you upgrade you already got a nice card for ur build.
as ppl were saying the extra stick of ram will do you good.