A question of roleplaying

I'm still struggling to decide between my various alts, currently my plan is to concentrate on just two characters, a tank and a healer. I've narrowed the choice down to: shaman and warrior (orc), shaman and warrior (dwarf, once Cataclysm arrives) or priest and warrior (Forsaken).

Dwarves are probably my favourite race in the game, followed closely by orcs. Having recently written the Alliance off as bland I probably won't go down that route, otherwise it'd be very tempting. The main appeal with the undead is that they're human-like, and hence seem to be better catered for by Blizzard. I'm often struggling to work out what my motivation is for some quests as an orc, whereas for a human / dwarf / undead it's more obvious. The drawbacks of this plan are several: I don't like the posture of Shank, my undead warrior; with a priest instead of a shaman I'd really miss reincarnation, water walking, ghost wolf and other flavour spells; and I'm not fond of the embittered outlook of the Forsaken.

So, I'm currently tending towards an orcy future, but I need to get more into the right roleplaying frame of mind. Because even though I'm on a PvE server, I don't want to play a MMOG without the RP.