Well only by Feb 13, by the time 8800GT is shipped,
the problem is that the timing is very very odd.. You see
the 9600GT and 98xx series will be released and then the 8800GT will seem like dust.
Bad timing because a cheaper 9600 GT is expected to perform better (not sure what margin) over 8800 GT, but at least faster than double of 8500 GT.
So the PC again will have a more robust graphics in real time matters.
AND, timb and lordblackadder did say they were working with EFI on making the 9 series Nvidia cards work on Mac Pro, they can't make promises but they sure sound like they know what they are doing and are committed.
So I might play the waiting game until Valentines day, see what rolls around. IF nothing happens and the hackers still can't help us, I guess 8800GT you should order. By the time a month rolls around you should be able to pick it up in the store right away and the 5 week wait wont occur again. Like when the x1900 XT just arrived, there was a wait, some time after they had plenty of stock and you could just walk in the store and buy it.
If I'm wrong with any of these, you can correct me, but this is the info that I have gathered.