Check these charts.
The X800 Pro is MUCH faster than the 9800 Pro. For older games, it won't mean much, but in BF2, you would see a BIG improvement in framerate and/or picture quality (because you could turn up the details higher and keep the same FPS). BF2 is an awesome looking game, and that's a very good price, assuming it's in good condition. An X800 Pro is very close to a 6800GT or a 7600GT, if that helps. I've seen the difference between a 5700 Ultra and an X800XL, which is similar to the difference between a 9800 Pro and an X800 Pro..and it was a completely different game. If you haven't seen BF2 in action with a good card, you will be blown away. Don't forget you're doubling your vram.
The prices on the newer cards mentioned earlier were apparently for the PCI-E versions. If you can find an AGP card of those models at those prices from a reliable source, you're luckier than I am.
If you're considering a $70 upgrade, I'll assume you're not up for a $700 upgrade real soon. Therefore, I'm not in your shoes, but I seriously doubt you'll find something better, and I recommend you hit it.