Here's the best recommendation I can give you:
Your motherboard supports both AGP and PCI. Because of the fact that you have AGP, you could go that route for a video card. If you look at this link, you'll see different types of video cards that will work with the AGP slot. The other thing to consider is the output. If you don't have a monitor that supports DVI (white wide connector with 24 pins) then your choices are narrowed to VGA (blue 15 pin connector. First let's look at the AGP cards:
http://www.tigerdirect.com/applications/category/category_slc.asp?CatId=318
You'll notice that some have more memory than others. The ones with more memory are better with respects to being able to process more video within their own GPU(graphics processing unit)
Some of the cards have DVI and VGA video out. Some of the cards have only DVI out. Not to worry because most cards have a DVI to VGA adapter. It won't run in true DVI output, but that's okay. If you have a DVI monitor, then you're in luck!
PCI - PCI cards are getting more rare to find since the newer technology is all PCIe or PCI-x, which your motherboard does not support, so your choices will be more limited. You can look at some options here:
http://www.tigerdirect.com/applications/category/category_slc.asp?CatId=319&name=PCI-Video-Cards&
Again, any of these will work too. It's going to come down to basically preference. AGP is just as good in MY opinion as PCI. Things to consider when buy the new card are:
1) Reputation of vendor/manufacturer
2) Price
3) Warranty
4) How good is their support is you have an issue (Of course you always have us here at FixYa)
I would be glad to give you a yeah or nay once you narrow it down. Also, if you like, you can read a little bit more about DVI here:
http://www.connectworld.net/cis/digital-monitors.html
Monitors that support DVI are more affordable and offer superior output resolution as opposed to VGA. I hope I've helped and if you need any clarification, just add a comment and I will be glad to respond.
Best Regards...Jerry