Okay, for fantasy gaming (by percentage of use):
My Own Creations (35%)
Monster Manual (30%)
Denizens of Dread (5%)
Oriental Adventures (3%)
Jade dragons & Hungry Ghosts (2%)
Creature Collection I (2%)
Creature Collection II (1%)
Monsters of Faerun (1%)
Fiend Folo (9%)
Monster Manual II (9%)
Epic Level Handbook (2%)
Legacy of Dragons (1%....but closer to 80% for my AU campaign)
I have to say, I like the WOTC productions best, but Jade Dragons & Hungry Ghosts is a great eastern monster book, and I am an old Ravenloft fan, so Denizens of Dread/Darkness gets plenty of useage, both inside and out of Ravenloft. I still use my own creations as often as published ones, and often revamp and file off the serial numbers of established creations to throw veterans of the scent. Finally, I don't tend to favor additional demon books, simply because there seem to be too many of them, and I find that the books I have now have pleny of fiends already in them. That said, I htink Anger of Angels has good potential, even though I haven't used it yet.