Lost Circuits recently put out
this review of a bench between the Ti 4600 (a la ASUS Ultra Deluxe), the Ti 4200 (again, a la ASUS Ultra Deluxe), the Radeon 8500, and the ASUS v8200 Pure (GeForce 3 Ti 500). I just happen to own the v8460 Deluxe...and the results are pleasing.
Of course you could wait a bit, save up, and get a newer better card. But by that time, there will already be talk of the next gen card...so its really a matter of how soon you want to play Unreal Tournament at 1600x1200 with playable framerates
edit
please post your new box's specs, so we can get an idea of what your video card will be living with. Getting a ti4600 might be overkill with anything less than a 1.3GHz proc.
Also, there is some fun stuff out with the nVidia Ti series, you can use a prog (which will remain nameless) to adjust some lowlevel settings, and turn your Ti into a
Quadro 900 XGL. Which run about $1000 - $1500. Performance increases in CAD/MAX has actually been observed.