My Favorites:
Original Naruto:
Fight: Episode - 48-50 (Rock Lee vs. Gaara)
Funny: Episode - 101 (Kakashi's Real Face) Filler one where they try to get Kakashi to take off his mask.
Classic: Episode - 6-19 Zabuza/Haku series. first huge Ninja vs Ninja battle, seeing Kakashi's Sharingan for the first time... it just sets off the entire anime.
Entertaining: Episode - 132-134 (Naruto vs. Sasuke)
Naruto Shippuuden:
Fight: Episode - 20-26 (Sakura/Granny Chiyo vs. Sasori) to me, there was just a lot of action in this fight. lots of combat. not just a "do one or 2 jutsus and the fight is over."
Funny: any episode with Hidan, loved that guy. made me laugh whenever he said or did anything.
*side note: favorite funny quote was when Sai was drawing a picture.
Naruto: "that picture's nothing special."
Sai: "yeah, you're right. just like your d*ck."
that made me laugh out loud big time, haha.
Classic: Episode - 3-4 (Bell Training parts) nothing is more classic than seeing a nostalgic reincarnation of that training exercise.
Entertaining: Episode - 162-167 (Naruto vs. Pain)