GOD The show's so GENIUS XD There's so many clever little puns, references and implied things in each episode that there's something new each time.
Like I only recently realized the reason the Satellite in Full Swing was falling was because the ball Haruko threw so hard it escaped the Earth's Gravity hit it (it's VERY subtly shown, and barely mentioned).
And how it imply a lot of the plot elements, like the indirect kissing or the possible arson, and let it be up to you. THe show gives back as much as you put in, it's AMAZING XD Plus figuring out what FLCL is and why things come out his head the times they do is fun too, it's pretty deep if you keeping looking into it.
That show would have been hard to write, I give a lot of credit to them XD
...I don't know... favourite eh? I guess I like Brittle Bullet. The whole sequence where they explain how NO worksm the Daicon V reference, it's good stuff, but I love all the episodes really.