I would like to repeat, I'm not a heavy gamer. So I won't tell you what video card to buy. However, I've looked at the differences between the 6600GT (of which i've used and known many people who own them) and the 7300gt. The 7300gt is an oddball video card in that they used the more advanced processor that the 7600 cards use.

HOWEVER, unlike the 6600 series, the 7300 series is an entry-level series, it wasn't designed for gaming, but more for home theatre stuff. On that note, stick with the 6600GT OR go for the 7600 series, which is the direct replacement to the 6600GT.

So there's my view on what to do with the video card, the 6600GT should be better then the 7300, and the 7600 should be better then the 6600GT.

As for processor, go for the Core 2 Duo, if you overclock, buy the cheapest, if not, go for a faster one.

That should be all you need to know.