Sertraline (Zoloft/Lustral) at 50mg a day (lowest dose) works incredibly well at keeping my anxiety and depression at bay, but I believe my problems are biochemical in origin (5-HTP and other supplements are useless and I exercise a fair bit). If your depression isn't biochemical, think long and hard about medication as they probably won't work, or maybe even worsen things.
You really need to try to get an idea on what it is that causes you to feel the symptoms of depression/anxiety before considering medication, but in the right cases, antidepressants can be a great thing. I've also tried Citalopram and Fluoxetine; neither were at all pleasant and I discontinued both after a few weeks. Sertraline I found to be very different, its more an anxiolytic than an antidepressant, but as my problems are mostly due to anxiety, this is perfect. If you do try something, keep the doses initially as low as possible - I think many of the problems people have with anti-depressants stem from the dose being too high.
A point with Mirtazipine - it makes you drowsy and causes a massively increased appetite. Something you should be aware of.
ETA: Ketamine might work, but is not sustainable in the longer term. I've tried it and doesn't last long at all. That said others have had great success with it, so I guess it goes back to the ol' trial and error (as is the case with all of this, unfortunately).