From everything I've read, they are very cool cards. I don't feel that my experience would be overly helpful, since my card is in a Shuttle small form factor box with less than perfect ventilation when compared with a large box and plenty of room. As a point of comparison though, the 5900Ultra would have the entire side of the Shuttle's case VERY WARM (bordering on HOT), whereas the 7600GT makes the same spot barely warm to the touch at all.
If you are interested, here are some pics of the box and the cards:
http://joe.murphclan.com/shuttle/
and this is the card placement... you can see why the case gets hot since the card is only millimeters from the case itself (the thing with with dual fans is the 5900Ultra)
http://joe.murphclan.com/shuttle/Dsc05287.jpg
Just for knowledge's sake, I have mine overclocked from 560/1400 to 580/1450 and my idle temp is about 45C, with gameplay getting up to the mid 60's C. This is hotter than almost any reports I've seen. BTW... I had this card at 625/1500, but VERY quickly everything got a purple haze/fog, so I backed it down some. I don't know if it's the memory or the GPU that is causing the problem... but it could be neither, as I've read that the PCIe to AGP bridge may in fact be the culprit.
As for your wife... I did see a noticeable performance increase when I went from a 5900XTV to the 5900Ultra, so I am sure that if you got your wife something in the 6600 range that there would be a very nice performance increase without it costing as much. Actually, now that I'm thinking about it, I have a good friend with the same exact Shuttle box that I have and he went from a 5700 to a 6600GT and saw a BIG difference in performance and picture quality, so I can verify that it would be a very nice upgrade for her. (actually... I'm on the phone with him and his description of the difference is "humongous")
Joe
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