These may have already been said but:
(of course, in the balance of our relationship, I'm a lot worse than she is though!)
- people who window shop from the middle of the street (in pedestrianised areas). They'll just stop walking at stare at a shop window from 5 yards away, meaning everyone has to dodge around them.
- people who get off the bottom of an escalator and then just stand there... not walking forward. Tourists on the tube are particularly guilty of this and it drives me nuts
- people who don't click things back into place. My girlfriend is forever leaving things "unclicked", like the lids to toothpaste, shower gel and the backs of mobile phones. She also regularly puts the kitchen utensils back in the wrong place - she won't put the good kitchen knives back in the knife block, but will put them in with all the old knives in the cutlery drawer!
(of course, in the balance of our relationship, I'm a lot worse than she is though!)