Wellbutrin is buproprion, it affects dopamine levels (um, like cocaine, but cleaner and not nearly as dangerous and I personally take it at the lowest dose possible) and it's the best anti-depressant that has worked for me.
Wellbutrin rarely spikes mania for some reason, and it doesn't cause weight gain, and can even help some people quit smoking or lose weight.
On the other hand, it makes some people feel like they're tweaking I guess. It's just what works for me.
I've tried SSRI's and they aren't really good for me at all. However, they work wonders for some people.
You really should talk to your doctor about what is best for you, whether you get "emo depressed" (can't stop crying over Hallmark commercials and hang on your boyfriend's leg like a six year old when he tries to leave the house, yell at people, etc.) or if you get "flat depressed" (numb, no feelings, empty, no motivation).