I geek out about optimizing keybinds, macros, UI stuff etc. so having a whole team to play with is wonderful. PvP is also fun (and I like to think that it adds a bit of flavor for the opposition too... I'm not one who steamrolls folks yet, so there's a lot of free honor to be had by running across me)

As far as progression goes - I pretty much just raid tank solo or run a DPS solo for current teir content.