Newbie Needs Help With Picking a Class

[Fanguru]

You could also consider necro.
You may not be invaluable to the group, but you can support it very well with heals/mez/manafeed. Add constant dps with pet, cheap to gear up, makes money easily.

You wouldn't be the most important person in the group, but you would be welcome.

Another option for a support is the ever popular shaman, as long as you don't mind spending most of your time casting cannib.