I don't get all the hate here for Keller. She was never my favorite but I almost never found her deserving of such vitriol. The only time she ever really annoyed me was in that Season 4 episode where she & Teyla got stranded on that planet and she wouldn't stop whining. But beyond that, I never found her so offensive. (Granted, I haven't seen Season 5 yet.) On the plus side, Keller was sexy and her romance made for an interesting McKay subplot.
Still, Beckett is my 2nd favorite Atlantis character of all time (after McKay). "Poisoning the Well" is far more interesting than anything Keller ever did. In addition to his interactions with McKay, I also really liked his scenes with Dr. Weir in "The Return." And although Keller is the sexy one, I find that, in a totally platonic, heterosexual way, Dr. Beckett is just kinda adorable & cuddly. It makes me want a Dr. Beckett plushie.