Parallels and Mac Pro
I tried out the update to Parallels for Mac yesterday. The good news is that it doesn't panic my Mac Pro instantly. The bad news is that it does panic it at least some of the time, and the worse news is that VT-x support is apparently disabled by the boot ROM on the Mac Pro. So everything I tried ran pretty slowly.
This is apparently a problem that afflicts certain Mac Intel Minis, and there are some instructions for adjusting the nvram to enable VT-x. But that's not something I can really fool around with; if my Mac Pro becomes unbootable, it would not be fun.
I think it's worth waiting a bit before Parallels is fully baked on Core 2 Xeons.