Aeris: This guy are sick.

Don Corneo (Da-Chao): I press this button and we'll have a SQUASHED TOMATOES!!

Cait Sith: Gya ha ha and Kya ha ha are plotting something. Wanna listen in?

Don Corneo: Okay, gotta get this off my chest. Whoo. Oh boy...I’m single. There I said it. (and here is looking for a bride?)

Priscilla: I'm sorry I mistook you for those Shinra Inc. (I laughed at this.)

Honey Bee Girl: Poo...I mean sir...please hurry.

(This next one is during the Nibelheim 'hallucination scene' at the Northern Cave)

Cloud: It's okay, Tifa. I wasn't affected by it. I wasn't paying attention to him!

(This makes me laugh because, was he just staring off into space or something?)

Gold Saucer Prompt in Battle Arena: Do you want to continue?
Your choices: Off course! No way!

I don't remember this one, but here's a way to find it. Go to Godo's house first in the Yuffie subquest, find Godo and talk to him. WHAT THE @#$% is he talking about?! GOO-GAH!

And my favorite:
Cloud: Let's mosey.