My experience with anti-depressants -- paxil, serzone, and now wellbutrin:
They did not lessen my depression. What they did was to kind of emotionally anaesthetize me so the depression didn't bother me as much. Nor did anything else. They allowed me to function. They did not help me enjoy life, or help me feel more like life is worth living.
I started HRT 5 months ago. Starting about two months ago, I noticed I was feeling happier (well, sometimes.) But, even bigger, my attacks of feeling suicidally awful have weakened. They still happen, but now they mostly elicit eye-rolls from me. I've started cutting back on the Wellbutrin.
HRT does seem to have had a weird side effect on me, though. Sometimes, when I'm not dealing with someone else, I just have this urge to sing along with the tunes in my head (I'm in a choir, so we learn a lot of tunes.) Sometimes I even have the urge to kind of dance along. Sometimes I think of things and start to grin, and, if I'm walking, I have the urge to skip (despite my not entirely healed sprained ankle.) Weird, huh?