Though I'm not convinced by Woody Allen's list, the fact that none of us asks to be born must certainly warrant consideration. And then the question becomes not, is life worth living, but, finding ourselves alive, is it better to commit suicide or continue living? And I think I'll only be able to answer that question on my death-bed (and depending on whether the intervening years/months/days/hours are filled with happiness or sadness, the answer will probably be different).
Anyway, I wish I had a friend like Woody. A pain shared is a pain halved (so I'm told - though I've yet to empirically test it). ;)