I did a lot of research on the ATI Radeon 7000. If you buy a true ATI branded card, the 7000 comes in several different forms. You can get PCI or AGP, 32 MB or 64 MB, with or w/o S-Video out. But not a single variant has Video >IN<. Non-ATI branded radeon 7000's *might* have video in, dunno.
I ended up buying an ATI Radeon 7000 AGP 64 MB sVideo out, for $70 at Microcenter. I love it. But no video in...
Also, I do have another card with S-Video >in< on a Mac. I've connected the PS2 there, and it looks like crap. general rule is that Consoles will look better on TV, and PC games better on PC Monitors.
If you try running a PS2 on a PC monitor, you will see all sorts of little defects... it looks real bad I tell you!