Has anyone else ordered the 2600 off of Apple? Maybe they have also got a call warning that it's not compatible with 06/07 Mac Pros? All the information we have in this (extensive) thread is based on peoples words and assumptions. This, however is a fact. The apparently incompatible 2600 works, so (although im no technical guy) the 8800 may also work. We should just, as many others have suggested to, calm down until the industrious Brits get their first batch's of cards in a few days.
incidentally, enjoy your upgraded Mac Pro, DrunkWally!
At last, a voice of reason!