What class mixtures have you found to be interesting/ good? Your submissions have no requirements, so they don't have to be optimal or anything. Heck, you don't even have to be fully sure they work really good together, just post things you think might be good. But, it would be cool if you gave pros and cons to the idea.

Here are a couple I have recently thought of, but to be honest, I haven't crunched the numbers or anything, they just seem like they would be pretty cool characters.

Knight//Crusader. As they are both essentially tanks, and they don't have much in the way of overlapping abilities, they seem to mesh very nicely. I would think the class abilities of the two complement each other rather well. And, as an added benefit, it just sounds right for your character to say "I am a Knight Crusader."

This may have some RAW issues with Eldritch Glaive not being a weapon, but I would allow it in my games. Warlock//Warblade. Has the potential for some MAD problems, but that depends on what invocations you go with on the Warlock side. But, a flying, energy polearm wielding guy using maneuvers sounds pretty cool.

Dragonfire Adept//Dragon Shaman. Some nice support abilities with the invocations and aura's, the class abilities of the Shaman, and the caveat that all the abilities from both classes that deal with the breath weapons only say "your breath weapon", this is a pretty nice combo. Of course, in my games, I allow a Dragonfire Adept to use Metabreath feats, so that might be a factor.