ahh. Colorful expressions.
Let me preface this with a caveat: I have a foul mouth (more
backstory is here.)
My all-time favorite phrase is, "For fuck's sake!"
If I'm in the company of children, or if I'm at work, my favorite phrase is, "Crikey!" said in a really bad Liverpudlian accent.
Some newer phrases that I have co-opted from Halo2 and such creative genius as
Red Versus Blue is, "team-killing fucktard."
Heh...another of my favorite phrases, "I'm gonna peg you into submission" comes from my favorite Kiwi. I have a New Zealander friend, Tony, who is awesome. He's tall and ripped, and sexy as hell (ex-military, volunteer firefighter, carpenter, runs his family's dairy farm, etc.). He is also gay, but that doesn't mean I can't admire his sexxahness.
Anyhow, last summer he was hanging out with me, my fiance, and our mutual friends, Evan & Jessica. The guys were doing some maintenance on their cars. My fiance was having some difficulty with his Toyota, and he yelled something to the effect of, "You cocksucking bitch!" at it.
Tony stopped. Looking at my fiance, he said, "Hey now, you've not only insulted me, you've also insulted Linne and Jess. You'd better watch it, boy, before I buttfuck you into submission."
Heh. The look on my fiance's face was priceless. In the spirit of Dan Savage's article on pegging, I have co-opted Tony's phrase and I regularly threaten to sodomize men who piss me off, usually with a strap-on (aka, "pegging") or whatever is at hand.

Hee!