The top of my list is from Blaze of Glory by Michael Pryor:
Aubrey Fitzwilliam hated being dead. It made things so much harder than they needed to be.
This particular opening line, for me, ticks all the boxes - you get a sense of the voice and character, it has a certain wow factor and it makes you want to know more. There's also a dry sense of humour to it, that instantly appealed to me.
Another favourite of mine is:
The early summer sky was the color of cat vomit.
This one's from Uglies by Scott Westerfeld, and while also being some unique imagery, it's the kind of bizarre statement that gets you attention.
Good things come in threes, so I'll add a third one that I love. This one's from The Scorpio Races by Maggie Stiefvater:
It is the first day of November and so, today, someone will die.
This one's darker than the other two, and it really sets a mood for the story. Like the others, you also get the feel for the voice, and it draws you in.
Now tell me yours!