Well, turnabout is fair play, and it looks like ATI is doing the same thing to Dell workstations.
If you go here and look at equivalent workstations with XP or Vista, you will see what I mean. If you pick one with XP, you get the following choices.

Now if you pick the same system with Vista, all the ATI cards go *POOF* but luckily the ATI sponsorship banner sticks around. That one must sting a little.

In any case, it looks like the problem is the same, MS marketing money. A quick trip to the DAAMIT web site confirms there are no Vista FireGL drivers available. If you are buying a precision 690, just avoid the Windows lock-in and go Red Hat. µ