I'm a bit of a completionist and I prefer dungeon queuing to questing.

I just finished getting all my classes to 15, geared with presets saved. I also did all the crafting classes to 15 and made a run of one of each item from the 16-21 crafting bracket, so I've got a well stocked and organized armory chest and lots of cross-class options

Are there any particular dungeon and class interactions worth noting? Anything really desired in certain dungeons? Anything useless or detrimental? Any key items I will want to find in dungeons, where I'd want to be a class that can roll need if it drops?