I also like the scene where Buffy meets up with Billy outside the gym and they talk, and the shots intercut, and every time we see Billy there's a street in the background with cars going by. It's so obviously a *real* place--real school, real road with real traffic. My sense is that they lost those moments of atmospheric versimilitude in later seasons as they relied more and more on sets.
The shot in "Out of Mind, Out of Sight" when Angel comes to the library to talk to Giles and they use the bookshelf case glass to demonstrate he has no reflection--showing Giles but not him.
One of the opening shots in "Prophecy Girl" when the camera point-of-view slides in across that deeply cool library roof and then descends inward to show Giles below. Then we get another shot of him through a window before we enter properly into his office. Nice.
I actually quite like Moloch the robot. I think that's pretty clever. Plus he looks like a comic book villain.
Owen in "Never Kill a Boy on the First Date" is proto-Riley.
Xander in "Teacher's Pet" walking into the chick's house and gaping in awe at her breasts the entire time she's talking to him. That's hysterical. Most shows on TV would be too timid to play it that way or they'd do it crudely, with a cringe-worthy laugh track. But Xander--NB--makes it perfect.
The scene in "The Puppet Show" where they get roped into performing and Giles smirks. The bit where they backlight Armin Shimerman's ears suggestively, capturing an image of devil horns. The ending, of course. To die for.
Buffy's mesmerizing excesses in leather and mini-skirted hookerwear throughout the season.
Xander's shirts, both terrible and wonderful, and his floppy hair and his edge of darkness, his teen-boy lust and single-mindedness, and the prop of his negelected and soon to be abandoned skateboard.
Willow in the Bronze as Xander is practicing to ask Buffy to the dance, at the beginning of "Prophecy Girl." Leaning in toward him with her big, puppy-girl eyes, happy just to be fake-asked on a date by her best friend.
Giles's insane paisley scarf. The hell?