Cheap-ish video card recommendation

[David Kramer]

I recently built a mythtv front end whose video card (random card from
my basement) isn't cutting it.  I can't get 3D/acceleration or
widescreen working with it, and it's hooked up to the PC port of my
livingroom TV.

The motherboard is old enough that it takes AGP 8X, which is a little
harder to find these days (everything's PCIe).  The only ones I've found
around are ATI, and I've had compat problems with ATI's lately,
especially since xorg has been removing older drivers from the distro,
and the proprietary driver won't work with the ATI card in there now.
Because of that, I'm leaning towards nvidia, but if you know for a fact
that an ATI card is supported with the proprietary driver, I'm willing
to listen.

Again, this doesn't have to be anything fancy, since I'm not doing
gaming on it.  I would even consider a used one.

Any recommendations?

Thanks.