I've got a massively old computer and I want to upgrade the AGP Gfx card. Any recommendations?

If the system is massively old, what kind of performance boost are you expecting?
Anyhow, AGP (4x/8x) cards don't get much better than the HD 4670. Example here or HD 3850. A HD 3650 /HD 3670 is a step down in performance but also a lot cheaper. Their nvidia equivalents would be GT 240/9600GSO (not available in AGP) and 7900GS (probably out of stock and no longer being made).
Depending on what CPU you are using, the likelihood is that the CPU will bottleneck performance of these cards somewhere between "a fair bit" and "a lot".

i'd shoot for a 7800GS or 7950GT/X1950. i'm using a Radeon X1950 Pro in my shop computer and it can actually run some newer stuff on modest settings. like divide pointed out the cpu will either make or break the upgrade, so make sure the processor is up to the task of keeping up with graphics horsepower or the improvements will be lackluster.

check ebay for AGP stuff...

+1 DBZ.

Also, what's your budget? The HD 4670 AGP is really expensive considering the performance that you'll get. Most of the new AGP cards (there are very few) have a high premium attached to them. You're probably better off just waiting till you can do a complete system upgrade.

Do they still make AGP Video cards these days?

Its possible to get one.

they do, this is about the most powerful one there is
http://www.newegg.com/Product/Produc...-337-_-Product

Sadly
For $120 too.

Dont forget to also ensure that your PSU is up to the task! Most recent AGP cards recommend that you use a 400w or more PSU. Nothing worse than getting a new AGP graphics card only to find that your PSU isnt juicy enough!

Just thought I would add that! Sorry if you had already considered it!

Good luck - let us know which one you get!

p.s I use a Sapphire HD3650 AGPx8 with a intel P4 HT 3.0Ghz CPU on an ASUS P4P800S-X Mobo with 2GB of DDR400 RAM and it is fine!