* In the Middle Earth game I play in, I think the DM only allowed Core PH classes, but my character has about 4 levels of (3.0) Shugenja.
* In the Dawnforge game I play in, the DM pretty much allowed everything and the kitchen sink. I'm playing a Bard/Hexblade and someone else is playing a Soulknife. The rest of the players are pretty much all classes from the DFCS or from AU.
* I recently played in an all-day one-shot as a Githyanki Psion. I think the rest of the players are all pretty much core with PrCs.
* In the campaign I run, I allowed core PH, OA (minus the wu jen), and a few 3rd party like GR's Shaman. No one is playing a non-PH class, however. This one started about 3.5 years ago. If a new player wanted to play something from the Complete books, I'd probably allow it after considering how to retrofit the class into the campaign world.