Well, i'm certainly no expert when it comes to GFX cards, but, i was looking at these three cards recently (albeit pci-e). Here's what i found out.
Generally the 7600 should have a slight edge on performance over the other two in most games etc, but it's a bit more expensive as you can see. If you can find a cheap X800 GTO2 get it, it's basically an X850 with a few of the pipelines disabled, but they can be re-enabled with a simple bit of software. But, by all accounts ATI's drivers are not the best.... so ??
In the end i got a cheap but brand new XFX 6800GS XXX which is as good as the GT Ultra version, + it loves to be OC'd so it may even be better than a stock 7600, time will tell.
At the end of the day it all depends on how much you want to pay and what you want to play. You mentioned a couple of games there which to be honest i've never even heard off, but, if i were you i wouldn't buy a GFX card specifically for one game. At a later stage you might fall in love with something else, FSX for example, which might end up playing like crap on your chosen card, yet play like a dream on a card you rejected.
So, as with many things in life, it's advisable to get the best thing you can afford at the time.
But, having said all that, the best advice i can give you is just hang around for a while till Jakg spots this thread and gives his advice.