What are some first lines to novels/stories/fanfic that you like?
LIT:

Miss Brooke had that kind of beauty which seems to be thrown into relief by poor dress. [Middlemarch]

In a hole in the ground there lived a hobbit. Not a nasty, dirty, wet hole, filled with the ends of worms and an oozy smell, nor yet a dry, bare, sandy hole with nothing in it to sit down on or to eat: it was a hobbit-hole, and that means comfort. [The Hobbit]

FIC:

Grief should be ugly. It should pull all the beauty out of people and leave them withered and ugly and deflated. That’s what it did to Giles. It made him old. It made Anya brittle and cold and unreachable. It made Willow and Tara drawn and hollow. It made Dawn small and faded.

But it made Spike beautiful. It softened his hard lines and made dead eyes alive with pain. Grief made him shine, and it made me want to soak it up like the heat from a raging bonfire, made me want to stand too close and get burned. [29 Linear Moves by yin_again]

Angel and Spike are race car drivers. Stop laughing.

Angel and Spike are race car drivers. No, listen.

Angel and Spike are race car drivers and neither of them have figured out that the track is a loop.

And so they go on. [Race by Dodyskin]

What are some first lines to novels/stories/fanfic that you remember off the top of your head?
I suck at remembering (verbatim) first lines from either lit or fic. I'm better with standout lines, such as: "And now the old story has begun to write itself over there," said Carl softly. "Isn’t it queer: there are only two or three human stories, and they go on repeating themselves as fiercely as if they had never happened before; like the larks in this country, that have been singing the same five notes for thousands of years." from O Pioneers! or, you know, that thing about medals and eyes and hardness.

What's your favorite first line you've written?
Almost *all* of my stories begin in the middle of something, typically in the middle of a conversation or an argument. I like opening the story with the reader being thrown off balance, having to catch up. That's great until you're me and you do it EVERY time. But I love this one, possibly my favorite single opening line of all time:

Xander opened the door to a trio of mismatched party hats. Looking into the shame-filled faces to which they were attached, he did what anyone would do the morning after a forgotten birthday. He opened his mouth to offer a stinging, day-late, cake-short rebuttal. Unfortunately, that simply allowed the straw from the beer-hat he was wearing to plop onto his chest and bleed his t-shirt into a deeper shade of orange. [Better Together]

What's the first line you've spent the most time on?
Oddly, this little bit of Spike/Angel from ...There's Fire. It was originally heading straight for purple-prose hell:

“Been a while since I’ve seen you do that,” Spike said as his fingers left his lips, sending streams of smoke to twist and spin, blending in the air with Angel’s. He dipped his head, his lips curling slightly. “Sure the soul’s okay with it?”

What's your least favorite first line you've written?
I thought I was SO clever, opening the sequel to Rodeo at the end of sex scene. Cliché! Cliché! It's soooo been done:

Xander’s hands fisted in dirty white sheets, his body shuddering as he heard Angel groan and fall against him, their skin pressed warm and close. Then a rough hand was pressing down on his back and Angel was rolling away.

*sigh* All of my fic is so old. Hi, you!