I personally would get the GTS because the cooler on the 8800GT is terrible. I do not like single slot coolers at all and dont trust them. Also the card is faster. This is actually why I bought the card you see in my sig. It is only ~4 or 5% better at my res of 1680x1050 than the 8800GT, but it has a dual slot cooler so it was worth it to me. Mine came with enemy territory quake wars, but I already have that game so it wasnt a deciding factor. My card was $345 at the time, but is now unavailable since it has basically been replaced by the 8800GTS 512mb card, which taks on another ~5 or 6% more speed on top of mine or so. Hope this helps.
Best,
3Ball