My new Mac Pro is in the mail. While the power of this machine is going to be awesome, I'm finding myself completely dissatisfied with graphics support. Here are some questions:

1) Why is the 2 year-old 8800 the best desktop graphics option available for the Mac Pro?

2) Is there any way to drop in a 280 for use in Windows?

3) Will it be possible, at some point, to be able to use a 280 with OS X?

4) What is the reason that higher end cards are not supported? Is it Apple's refusal to come up with drivers?

Thanks in advance.