Character help

I suggest you start out with what your comfortable playing. Now if your looking for anything specific then just go for for the basics 4xman team Ill choose all elemental shamans or enhancement, 5xman, well tank and heals of your choice and DPS well if u want minimal worring like me about what my dps are going to do for now well all the same class. I started out recently doing LFG and its a pain with just four because of the wait for other players. Now if you was running a 5 man team then u can easily run dungeons all day. I just started doing this with 1xPaladin, 3xShaman,1xDiscPriest and let me tell u at times its a PAIN but its what u want out of the team that you have to work toward. Oh yeah Disc Priest till LVL 38 suck something mayor.

[Ualaa]

Four druids are another option.

Druids can spec Balance, which is going to play similar to an Elemental Shaman.
Feral spec is going to be similar to Enhance.
Resto spec is resto spec, at least as far as the role goes.

Druids are capable of four specs and all three roles (Damage, Heal, Tank).
Shaman don't have the equivalent of the Guardian spec, but Druids can spec as a tank.

If you want one class that can do dungeons as well as quests...
Because they can be each spec, they can queue for dungeons and select the requisite roles... so they can use the Dungeon Finder.