Most memorable moment? :? Well, I have a lot but I'll try and keep the list small.
During L'Arc~en~Ciel's "Awake" Tour on the last song, "Hoshizora", when Hyde cries.
During L'Arc~en~Ciel's Shibuya Seven Days Tour when Hyde forgot the lyrics to "Heaven's Drive" soooooooo cute!!!

During L'Arc~en~Ciel's "Heavenly" Tour when Ken falls down lol
Also during "Heavenly" when Hyde goes up to Tetsu during "C'est La Vie" and hugs him from behind. Tetsu: *blush*blush*blush* Hyde: *snuggle*. Yeah, it's adorable.

When Hyde and Ken went on Best Hit TV

L'Arc~en~Ciel's acoustic performance of "I'm so Happy"

Hyde's solo performance of above mentioned song (Rock version)
On the set of Moon Child (great way to start a sentence, ne?) when Gackt and Hyde were rehearsing the shounen-ai-esque moment. Hyde was so shy and Gackt was so...NOT shy!

All Gackt's appearences on Utaban
All the many, many, many, many, MANY times Gackt's jumped someone on stage...eh heh

can't help it
Miyavi's ADD moment during his first time on Hey, Hey, Hey
On the set of Ore-sama when Miyavi'd randomly break into song
Any and all Antique Cafe clips
OKAY, I am stopping that before this post gets so long it strangles me.