I have a prebuilt Inspiron dell desktop 560MT with a Intel G45/43 express chipset. I wanted to upgrade for gaming purposes and started looking for a newer card. Then I remembered I bought a Geforce 9500GT DDR2-512MB DVI card about a year or two ago and never got around to installing it into anything. So I guess my question is, If I install the Geforce card will it be better or worse than the G45/G43 chipset.
If you'd like any beefier card, then you should start looking up for PSUs (power supplies) also.
What's your current monitor resolution? Are you planning on a 24" or bigger monitor?
On a wild guess, if you're on an 1650x1080, your bottom line should be something in the lines of a 6850 or a GT550ti to get all the eye candy in modern games (or most of them). Higher than that, you'd have to start looking at a 6950 1GB or a GTX560ti (GTX460 1GB too).
The PSUs that can accompany those cards are 500W and above. Don't have models in mind, but I've seen Corsair and CoolerMaster ones running some-what cheap and with good quality.