Thanks for all the replies to this, I was really more curious as to "how well" games in wine would work with the gallium driver compared to classic mesa rather than "how fast", but what you've given me is enough to make me at least give the x1950 xtx a shot (EUR40 seems reasonable for a new one, right?).
A couple of questions though;
I got my hands on an old x1950 pro agp card to test it out for myself since I last posted, however I ran into a couple of issues, highlighted here.
Is this terrible performance with kms and agp cards the norm? (~300fps in glxgears, but desktop is unusable)
I tried the airlied's "drm-for-2.6.35" kernel, but it was no different than a 2.6.32 kernel, even though it looks like numerous agp fixes went in to that tree.
Anyone else see that "undefined symbol: _glapi_get_proc_address)" problem?
Probably just something screwy on my end...
Even though it's unusable, with the gallium driver glxinfo does report the following;
Code:
OpenGL renderer string: Gallium 0.4 on RV570
OpenGL version string: 2.1 Mesa 7.9-devel
OpenGL shading language version string: 1.20
However, isn't r500 hardware limited to opengl 2.0 with GLSL 1.1? 
One thing that did work well for me though was the i2c hwmon support, with the (slighty patched) lm63 driver I was able to get two temperate readings as well as the fans' current pwm value in conky, very nice!
I know this is utterly dependent on the sensor chip used, but do they all report the pwm value, or has anyone seen any that report the fans actual rpm?
Anyways, thanks again for all the replies.