I just watch stuff that looks interesting and move onto the next. I don't think I've ever watched a series twice...

I still watch Naruto once and a while when it's not in filler/recap mode.

Some series I liked....
Trigun
Cowboy Bebop .... Trigun + Cowboy Bebop =..... TAINTED DOUGHNUTS!
Outlaw Star
Ronin Kenshin
Tenchi Muyo
Ai Yori Aoshi
12 Kingdoms
Kare Kano
Gunslinger Girl
Gundam Seed
RahXephon
Record of Lodoss War
>> BERSERK <<
S-Cry-Ed
Air Master
Hikaru No Go
Saki
Welcome to H.N.K.
NANA
Full Moon wo Sagashite
Hajime No Ippo
Samuari Champloo
Eureka 7
Chobits
Code Geass
Spice and Wolf
Last Exile
Love Hina
Tengen Toppa Gurren Lagann
Dennou Coil
Macross(s)
Mahoromatic
Elfin Lied
Noir
Escaflowne
El Hazard
Haruhi Suzumiya
Kimi ni Todoke (such a cute series... haha)
Sekirei
Kiddy Grade
Ichigo 100%
Saikano
Ah My Goddess
Moon Phase

Comedies:
Azumanga Daioh (simply awesome.)
School Rumble
Jungle Wa Itsumo Hale Nochi Guu
Ebichu (echii comedy. You'd understand my avatar if you saw it)
Excel Saga (AAAAACCCCUUUUURRROOOSSSSSSSSSSSS---SUUUUUUU)
Ouran High School Host Club
Gokusen
Kyou no Go no Ni
Lucky Star
Lovely Complex


... omg I better stop before I start to realize how much time I've wasted watching anime.