I have a few that tend to follow me around...
When someone makes fun of me in a friendly way: "*****, please..." or "Die in a fire.."
When a plan of mine goes terribly wrong: "The goggles! THEY DO NOTHING!"
And I've got an annoying habit of breaking out into song if someone says a line that fits... for example, if someone says, something about bicycles, I'll break out into the Queen song xD
I think the only other one I remember is telling people that, "Nobody loves you... not even Jesus." which gets me horrified looks from particularly pious folk. I'm sure I've got more, but I don't remember them...
Edit: My curses tend to follow a pattern, too.. not my more elaborate ones in which I try to prattle off the longest string of insults I can before running out of breath, but just my quick, under-breath ones... it's either "Damn", "Fuck", "Shit", or "****".
Otherwise, there's just my usual ritual of saying, "Fuck my life.." when something goes wrong.