I assume you got your mount yet?
After the recent patch, they reduced the level that you can get a mount from 40 to 30. since you hit 30, you can now get your mount.
And since you're a Warlock, your mount is 'free'. You just have to pay the price of the spell.
And yes, Warlocks rock. My main is a Blood Elf Warlock, and is currently the highest level character I have (60). Haven't started my mount quest line yet. But will soon. My second highest, and also good, is my Night Elf Hunter at 54 (soon 55). Also a good and easy class to level.
And while Warlocks rock, they are not perfect though. After all, they can only wear cloth armor. And while they rock at a distance, up close and personal, things go down hill. And of course, rogues, especially those speced to be assassins, besides sap, they can potentially kill you with one hit (pvp of course).
Still, they are certainly a great class to play. My favorite strategy, being affliction and all, send the pet first, then start cursing the target. First the healing one, then the ones that cause damage over time. Drain HP, and when it gets low enough, drain soul. For 'quick' damage (not really quick since it takes time to cast. More like, when it hits, a lot of damage is dealt when it hits), shadow bolt it till it dies.
Can't wait till I'm 70 with that one.