I originally rolled a mage, because DPS was cool, and my original connection (40k dial-up) was too slow for a melee class.  Mashing the same sequence of buttons endlessly then going oom to death got boring.

I rolled a shaman because they did some melee, spell DPS, and was able to heal (I liked my new-found survivability)

I heard that the Priest was the most versatile class in the game, had decent survivability, and was always in demand. 
So I rolled a priest specced shadow (because its the only way to level)  on my first RFC run I recieved my first flame ever.  It was quite enjoyable to be insulted by people who couldn't put a sentence together. At the time, I didn't know that they wanted me to heal  :oops:   
I got 3MB DSL at around lvl 45 and it made a Huge difference
Seems like I've come a long way from there.

During one of Boulderfist's extended outages, I rolled a tauren warrior on the Thrall server.  I hated it.  I died ALOT.  RFC and WC were a nightmare.  I was good at holding aggro, but most healers really suck at lower levels.

During another of Boulderfist's outages, I went over to the dark side and rolled a gnome warlock on Gnomeregan and was very surprised.  I fing that I hate the alliance now, more than ever.  On the other hand, the warlock class is Amazing in its soloability.  I found I was able to fight multiple opponents with ease at level 9 (3 mobs at once lvls 9-12 outside of the gnomeregan instance for about an hour straight.  Really enjoyed pissing off the allie noobs by DOTing everything in sight so they couldn't grind them).  If only allies werent so friggin Annoying, I would have continued to level that lock, and it might have been my main.  As it stands, BC=BElock4me