In golf, when on its last bounce your ball goes into the lake: Fuck.
Plain and simple.
Contender : Brad Pitt in Fight Club. Of course the soundtrack itself stopping for emphasis does help.
Depends on context, but I will have a special place in my heart for “feck” for always and forever, courtesy of Father Ted.
FECK!
ARSE!
DRINK!
“I don’t give a flying fuckleduck!”
I went on a beach vacation with a buddy once. I left my watch on at the beach. He went on a tirade: “When I’m on vacation, I don’t wear a watch! What’s wrong with you?”
Later that afternoon, he had the nerve to ask me what time it was.
“It’s FUCK YOU o’clock, that’s what time it is, Mr I Don’t Wear A Watch On Vacation. It’s FUCK YOU O’CLOCK.”
Okay, I will so borrow this!!! 
I used to work with a colorful young woman who had an expression I had never heard before (or since) but find myself using it on special occasions.
Well, shit the bed and fuck me running!
Always liked that one.
I wonder what James Lipton’s favorite f-bomb is.
And the syphilitic monkey that sired you and the $2 crack whore that whelped you and when you’re finished with all of them, fuck the midwife who should have fucking drowned you at birth, you fuck.
But my personal favourite is when something goes badly wrong and you can’t do anything about it, all you can do once you understand what’s happened and the consequences is to simply say “FUCK” loud and hard and harsh, like a sudden slap to the face.
A quick scan and didn’t find my favorite usage. From one of my favorite films as a kid, Heathers.
“Well, fuck me gently with a chainsaw.”
Incidentally, a friend recently mentioned to me that he once knew a fellow who would use fuck adverbially, e.g., that’s a fuckingly good pint. I’m working on figuring out how to incorporate this into my own speech patterns. 
I’m prone to road rage, although it’s less that I’m irritated and more that it’s entertaining for me to come up with new ways to swear at people. So I do. Sometimes my heart just isn’t in it, and I kind of trail off in the middle of it…
ANYWAY, one day on my evening commute a couple of cars did something egregious, and my muse was with me as I shouted, “YOU STU-PID SILLY SLUTFUCKS!” and then the heat was gone as I giggled about it. That’s my favorite so far.
My go-tos are “MO-ther-fuck”, and if I’m really frustrated, “Oh for fuck’s sake.” I don’t know why it’s possessive for me, but it is.
I’ve always liked the alleged quote – affectionately mocking the fondness on the military’s part, for highly copious and repetitive foul language – as follows.
Soldier griping about his malfunctioning rifle: “Oh, fuck ! The fucking fucker’s fucking fucked !”
Close to using all the parts of speech while he’s at it.