Card to replace Sapphire ATI X1900XTX

So I built a new rig and am still using my trusty video card...a Sapphire ATI X1900XTX 512MB PCI-e x16. My old parts got put in another case as a secondary machine. Now I need a new card for the secondary machine so I have two choices

1. Upgrade my primary machine with a new video card and slap the 1900XTX in the secondary machine.
2. Get a budget card for the secondary machine and keep the 1900XTX in my primary machine.

Am not sure at this time that I want to go balls out with spending several hundred bucks on a state of the art video card so am opting for #2. What would be a good card to buy that is equivalent to the 1900XTX performance. Just something to play Doom3 and Quake4 with. The CPU and RAM are all more than capable and the 1900XTX used to do the job no problem. Am just looking for a card maybe under the $75 mark. yes I know its a budget card but its only for a secondary machine.

Thanks for any advice.

~A