use a mouse, but I (not kidding) have topped the charts on pvp with a touchpad (use your middle finger as the cursor, click with your index). did some amazing things with a touchpad, didn't cripple me at all.
I would suggest a buying a mouse, but if you can't afford it I would make a shadow priest. theres 3 dots, 2 bursts, and MF. All you have to remember to do is to keep your dots up.
Honestly, Play any class. If you know the class well and like it you will find ways to improvise. I play a restoration/elemental Shaman and I play on my laptop all the time. I wouldn't suggest raiding but 5 mans and questing. Psshh, easy. I did the Vashjir dungeon with some guildies and didn't even wipe once.
I've been using the trackpad on my macbook for 1.5years of raiding/questing/pvp and I will never go back to using a mouse. My hands are right in front of me and everything is close enough so that I barely have to move my hands to do stuff.
I top charts, I raid often, I have no trouble at all without a mouse, and prefer to not use one.
I've been playing without a mouse for about the past two or three years (yes, with raiding!). It has really taught me a lot, and I am a much better player for it. and yes, I keyboard turn. and yes, I'm using a macbook pro so my touchpad had maybe a little more functionality than others. for example, i can right click by touching the pad with two fingers. it helps.
if you're just leveling you can really do anything with just a keyboard and a touchpad. don't forget that control click can also act as clicking the right mouse. just takes practice.
I have a pally. lock. shammy hunter. leveling a mage and a dk. I do just fine with all of them I'm just very dexturous(sp?). but I also play monster hunter on the psp and they both require some serious finger strength. like everything just takes practice.
Thanks for the replies, like i said, its just casual 1-2 hours 1 or 2 days a week when im not at home to keep me entertained, was playing around with a hunter and whilst it took a while to get used to, its not that hard