I'm glad to report that everything I've tried has worked thus far.
To save the gamers out there a lot of reading I have not attempted to establish this card's 3D performance beyond compiz effects and google earth. However, I see no reason to assume there will be problems.
I have a dual monitor setup using the 'flgrx' driver, compiz installed with desktop cube and wobbly windows (I'm easily amused), and I use the system for general office drudgery, light programming, various 2D and 3D CAD and EDA packages, and video.
|What doesn't work:|
Getting the open source ATI drivers ('ati' or 'radeon', I'm not sure which) working with compiz proved too complex for me. After switching to ATI's close source drivers ('flgrx') compiz began to behave, and I suspect things would have gone a lot more smoothly had I not made such a mess in my attempts.
If you have no interest in compiz you may be perfectly well served with the open source drivers. I had no problems with mild use of 3D and extensive use of desktop 2D.
|What was done to make it work:|
Nothing is really required, though if you suspect you'll be needing lots of 3D or using compiz I'd recommend using ATI's drivers as early in your install as possible to save later grief.
The switch to 'flgrx' is well documented and may change, so I will not cover it here. The process was once terrifying and is now very simple and largely automated.
This card is equipped with HDMI audio, and that can cause a lot of trouble if you have a complex soundcard install to worry about. If you don't make use of it don't be afraid to blacklist the module so it doesn't load on boot! Relevant google keywords are HDMI, audio, modprobe, and blacklist.
This should not be necessary, but it can help rule things out while troubleshooting.