There would be improvement, yes, though not enough to be worth the price of the card. What resolutions will you be playing at?
If I had to guess, you could play at 1650x1080 with high settings getting 30-40 fps. Anything above that would mean lowering detail.
You might want to consider building an entirely new computer for the new games.
Thanks for the reply. I wouldn't mind playing Black Ops at 1280X1024 or 1400X1050. Just that I'll be able to get good FPS to enjoy the game in Multiplayer. I'm not a heavy gamer, I can play COD Modern Warfare with great frame rates and WaW with decent frame rates. If I can get decent improvements with the new card then I'm ok with my computer right now. I will wait till summer to build a new PC.
Please input your experience and knowledge. If the HD 4670 won't improve much over my 8800GT then which card should I go for for major improvement with my current PC. or bottleneck?