One of the reasons I like playing draenei and tauren are connected to the classes I like to play: shamans, warriors and DK's are the only classes I've consistently gotten to max rank, and in all of those cases I tend to play large characters. When race change became available I agonized over it (silly as that is) even though I'd always said I'd go draenei because I'd grown so accustomed to the way my human character moved, and watching old avi files of Burning Crusade fights I'd tanked really brought it home to me. In changing my character's race, I've changed his silhouette, I've changed the way he swings a weapon, I've changed the way he looks in every aspect of the game. I don't do that spinning one handed smash when I tank anymore, it's much more of an arching, down-angled slash. My Shield Slam is different.
Granted, I'm okay with that. But it got me thinking about why I choose the races I do and the classes I do.