The below thread on In 'n' Out makes me wonder what IS the best burger in SF (I happen to be one of those who doesn't "get it" when it comes to their cultishly-loved food). I don't eat meat often but there are times when I just want a giant hunk of fatty fatty luscious bloody beef. When the urge strikes I *definitely* forego fast food (anyone else find Fast Food Nation life-changing and stomach-turning?), preferring to eat at restaurants that use high-quality beef.
As such, I typically enjoy Burger Joint and, for a guilty splurge, any of the Barney's chains (mm, Carribbean burger). I have heard great things about Rosamunde's burgers, haven't had one yet. I don't eat cheese so things like Zuni's bleu cheese burgers are lost on me. I also generally eat burgers utterly plain save for grilled onions and tomato if they are ripe. So the bun and beef quality are paramount.