I have an x800XL card with 256 MB.
That video card is only 2.5yrs old. It wont have any problems running this monitor on the desktop.
With regards to videos/movies, you dont need to worry about running interlaced or progressive (in fact this is the first time Ive heard of someone requesting details of interpolated stuff, with respect to video cards or monitors). Videos will run fine. If you do have interlaced video and wish to run non-interlaced, then just use ffdshow.
With games, when you run them in 4:3 format, what will happen is you should end up with 2 black bars on the left and right sides of the screen, effectively forcing the screen to use the 4:3 ratio. If your video card isnt fast enough to run some video games your frame rate drops, then you can always change the resolution to a lower one. Obviously the image suffers (only slightly), but dont think that you are stuck with the native resolution - this is not the case - resolutions on TFT monitors can be changed just as easily, as on the old CRT monitors.
In fact when running games, I dont think you can even run in an interpolated mode, can you? No video card drivers or game settings that Ive seen have ever given me this option, unless you are using some very special program that allows you to do this?
Hopefully someone else will give their thoughts on this subject though, so its best you wait for someone else to confirm what I have said.