I wouldn't waste my time on a production style profession (blacksmithing, leatherworking, tailoring, enchanting, etc) unless maybe it's engineering for a few PvP tricks. Gathering professions (mining, herbalism, etc) are typically more useful for making cash on the side while you level.
Rogue is probably the best first timer class IMO. Even soloing the combat is fairly fast paced and takes a bit of attention. Plus sneaking around to explore kicks ass. Warriors are about as easy to play but until higher level (and even then only for tanking/pvp) you tend to drift into a state of just autoattacking for the most part and it just feels less engaging to me than a rogue (I have a 60 and a 55 warrior and a 60 and a 39 rogue).
Priests, Paladins, and Mages are pretty damned boring to level imo. Mages can level fast but you basically just cast the same 2 spells over and over again. For Priests and Paladins levelling solo is mind numbing, slow, and boring as shit. Later as a priest you can spec enough shadow to where you can do some respectable PvP but they still level slow as shit. Starting around 40 priests and paladins can solo practically anything anywhere near their level just very slowly.
Shamans and Druids are kinda unique and you can basically kill anything. Druids are fun at first when you get new forms but I always tend to find myself spending all of my time in bear (retarded warrior) or cat (retarded rogue) form when levelling and only changing to heal up when needed. Shamans are kinda neat at first dropping totems all over, healing, frost shocking, wind furying, etc. After a while it always seems like I just end up meleeing and healing occasionally tossing down a totem for variety. Maybe I just have shit for attention span.
Warlocks are a little slow starting out but gain more and more versatility as they level. They are probably the hardest class to play really really well but if you are good at it and can get used to making use of 424 different hotkeys you can dominate in PvP (or you can play a rogue, hunter, mage, or shadowpriest and be nearly as effective with half the effort).
Hunters are kinda fun if you like pets. You can charm all kinds of animals and name them silly degrading things to amuse yourself. Actual levelling always seemed to degenerate into- aggro the mob, send in pet to take hate, turn on autoshot, repeat. Which to me just gets a little boring.
Yay for rambling.