Ive hit 60 with an orc hunter, i think horde is the side to play all the retards join alliance
anyway, Hunter is a nice class easy to level and grind, warriors tank (mainly defence) priest are always wanted, sadly take 2- 3 time longer to level them then anyother class
race wise pick one that has abiltys close to the class you want, trolls are great rogues/hunters because they get a bow and thrown bonus, orcs get an axe and pet damage bonus so there good hunter/locks
I like Hunters, Locks, Warrior and Shamans, but to each his own just roll a few characters and play around