I just recently reinstalled OFP after a year+ hiatus and began having the freeze, crash, the D3D error: cannot create 3D device, and then having to reboot to get directX working again. I read the Avon Lady's FAQ (Thanks AL) and searched through all the forums looking at the suggestions supplied. I tried the "-nomap" switch which delayed the problem for about 45 minutes until it started up again. I noticed it mostly when switching back and forth from scoped weapons, which may or may not pertain to the problem.
I began playing with settings before I did a dreaded rollback on all the drivers. What remedied the problem for me was reducing the audio acceleration to the basic setting and making sure EAX and hardware acceleration was disabled in OFP. My system specs are:
Win XP Pro
Athlon 1500+XP
ASUS A7V333 Motherboard
512MB RAM
Geforce 3 ti200 128MB
SoundBlaster Audigy 2
The Geforce 3 and Audigy 2 are on the latest drivers. Both are also sharing IRQ 16. I had to reduce the sound acceleration with both Hitman 2 and Hitman Contracts as well to get sound at all. The only thing I've noticed sound wise is a really light crackling every-so-often, which is better than going through the headache of rollbacks and not being able to play the game at all.
Figured I'd share my findings since the remedies I've read mostly pertain to either fixing the graphics pipeline for graphics problem or focusing on the sound pipeline for sound problems. My money is on Creative and their lovely drivers.