Yeah, I thought some of those things could be possible.. Temps stay under 70C at load and my fan is set to run at 45-50% when I'm gone (SUPER loud but the card stays pretty cool. 100% competes with most vacuum cleaners in the noise department). I'm not over clocking it at all and its just a standard, reference board. So I guess that leaves either the drivers (which I didn't use Beta drives, just the most recent drivers from AMD, or the fact that it is an AMD card and F@H hates them... I might have a go again at the drivers I suppose..
As far as a bad WU, after the first time it happened last night, I deleted the Work folder to clear out any wandering WUs... It recreated the folder and got back to work, but then same problem this morning. wooo!
Fortunately, the CPU client is chugging away! Operating somewhere just under 4k PPD. The Q9550 is quite incredible. Just put it in, OCed straight up to 3.8GHz and has been running at about 100% load on all 4 cores for 3 days now without flinching (this morning I brought it down to 3.63GHz for my own peace of mind). Runs a little hot, mid 60C-70C, but that's not too bad.