best for side effects, best for efficacy, best for ocd, best for depression? Need more info regarding best for WHAT exactly.
Briefly, going to answer these from what I've heard..
Most likely to work on OCD = Clomipramine, Paxil (high serotonergic meds)
Most likely to work on depression = Zoloft, Wellbutrin, Parnate, Nardil,
Most likely to work on Panic = Imipramine, Nardil
Most likely to work on SAD = Nardil, other GABA based drugs
Least side effects = Cipralex/Lexapro (most selective SSRI I believe)
Most sedating = Remeron
Most likely to kill libido = Paxil, Celexa
Just off the top of my head, don't take this too seriously, it's more trial and error. See what works for you