Most of the services are already shut down. I've got cron, ancron and CUPS running. That's about it.
Tried the "nomodeset" flag. Had the same results as without it, except that my mouse was a lot more "jumpy". The issue seems to happen mostly right after a fresh boot or when coming back from a suspend. The system will be fine for a minute and then lock up for 30-60 seconds. Then be fine for a few minutes, lock up again and then be fine for hours. Or until the next suspend/resume, when it'll lock again.
During the "lock" time, my desktop will be completely unresponsive, except the mouse will move. But I can switch to a text console and run commands from there. Again, running "top" shows less than 10% of my CPU being used, about half of my RAM is used. No swap is being utilized and no programs seem to be grabbing CPU time.
I ran Fedora 12 on my five year old laptop with about a third of the CPU speed/RAM of this new one and it works fine on the older machine. So I'm assuming the issue is related to the newer hardware.