Which style of battling do you prefer? Up close hitting things, or shooting arrows/spells from a distance?
I'm not going to base my rating on soloability, since gameplay has gotten much easier and I have always felt that the real game starts at endame anyway. I'll instead just think about the classes themselves and their overall playstyle and in that frame of mind I'd say that I would've given the nod to melee back in the days of D&D or turn-based Final Fantasy games, but not in WoW and other modern MMOs.
Melee is still an effective battling style, home to some well-regarded classes with massive player appeal and solid spots in PvP and in Raids. They hold the base of a party with their Tanking, and Rogues are widely considered the most annoying classes in PvP thanks to their stealth. Amazing stuff.
These days, however, it's difficult for me to get excited about a new melee class, even one that heals in melee range. The trend seems to be for bosses to be designed more and more to favor ranged positioning and movement, the playstyle is a lot of the same quick button mashing, a lot of their abilities focus solely on weapon damage with effects added on, and they leave me thinking, "well this is fun, but I'm in no hurry to get it up to Level 90."
Ranged classes, on the other hand, get me geeked. Minions & pets, lore themes, elemental powers, interesting support abilities...all things I like in a class. If I were to rattle off some of my all-time favorite talents, most of them are magical in nature (Metamorphosis, Living Bomb, Spirit of Redemption, Starfall) and only one is a melee (Cloak and Dagger).
(Last time I saw this poll on another forum around WotLK, Melee actually was in the lead (I think it was something like 61% to 39%))