These are shows I have that are not complete series sets--either they are still going or I just am missing a season or two--either way, I own at least one season of each of these:
Fringe
Star Trek: The Original Series
Spartacus
True Blood
Game of Thrones
Walking Dead
Futurama
Family Guy
Simpsons
Robin Hood (BBC)
Vampire Diaries
Supernatural
Modern Family
Raising Hope
Community
Parks & Rec
Mad Men
Justified
How I Met Your Mother
Big Bang Theory
The Mentalist
Rocky & Bullwinkle
Human Target
Adventures of Young Indiana Jones
30 Rock
The Addams Family
Adventures of Superman
Alfred Hitchcock Presents
Animaniacs
Babylon 5
Bones
Castle
Brotherhood
Curb Your Enthusiasm
Californication
Caprica
Dallas
Dexter
Dick Van Dyke Show
ER
Eureka
Everybody Hates Chris
Ghost Hunters
Gilmore Girls
Gossip Girl
House M.D.
In Living Color
Always Sunny
Jetsons
Jonny Quest
Legend of the Seeker
Lois & Clark
Murphy Brown
Night Court
NewsRadio
Nikita
Northern Exposure
The Office (US)
One Tree Hill
Sanctuary
Saturday Night Live (although they've only released the 5 seasons I have)
Saved by the Bell
Scooby-Doo Where Are You
Scrubs
Three's Company
Unsolved Mysteries
West Wing
Will & Grace
Xena: Warrior Princess