The best option in my opinion would be the 4650 that gkay09 linked to. It would be the best match for your CPU and has GDDR3 memory on the card. Buying a card with GDDR2 really isnt a good idea as the GDDR3 cards are so much better.
The other thing i would say is if budget allows it upping the Ram on your machine to 2gb will help a lot with newer games also. There is always the option of overclocking your P4 if you fancy ?