Of all time...

1. Buffy the Vampire Slayer
2. Angel
3. South Park
4. Veronica Mars
5. Gilmore Girls
6. 24
7. Battlestar Galactica
8. Freaks and Geeks
9. Lost
10. The Twilight Zone

(Notable mentions...Aqua Teen, Sienfeld, Firefly, Alias, Clone High, Arrested Development, Thats My Bush, The Office (US and UK))

Best shows of the year on the air right now...

1. The Office
2. Heroes
3. BSG
4. Lost
5. South Park