Enchanting is a pain in the ass. Tailoring won't serve much purpose until it's nearly maxed, as you'll actually be going through quest reward gear (as are Leatherworking and Blacksmithing).
I'd pick two gathering professions and just go nuts on the Auction House. Then later when you're higher level and have the gold. You can pick whatever you want and farm the materials more easily. Or just buy them off the AH if you've got the gold.
Personally, I think Herbalism is the way to go. There's a few zones where the herbs keep spawning and you can spend hours just picking one after the other and selling each stack for 20g+. I also got into Inscription recently and in about 2 hours I got it from 297 to 504. Easiest profession hands-down.
As far as Warlocks go...
I've played them a few times, but never got passed lvl 25. Though I've done some lvl 85 Heroics with some before and they're OP as fuck. Makes my Mage look like a dipshit.