Estimated viewing times are based on an average of 42 minutes per episode (22 minutes for half-hour programs) without commercials breaks.
Recommended viewing sessions: 2 episodes per weeknight (M-F) or 8 episodes per weekend.
FYI: All shows add up to about 1,015 hrs (just over 42 straight days). Summer (Memorial Day to Labor Day) is only 99 days with 14 weeks and 15 weekends.
Also: Only shows streaming at least one full season as of May 23, 2012 were included.
1. Angel

Seasons: 1-5
Episodes: 110
Total viewing time: 77 hrs
Weekdays only: 55 days (11 weeks)
Weekends only: 14
Streaming on: Netflix, Hulu+
Mad Men's Pete Campbell joins the cast in season 3.
2. Buffy The Vampire Slayer

Seasons: 1-7
Episodes: 144
Total viewing time: 100.8 hrs
Weekdays only: 72 days (14 1/2 weeks)
Weekends only: 18
Streaming on: Netflix, Hulu+
Seth Green (not pictured) is also on this show.
3. The City

Seasons: 1-2
Episodes: 35
Total viewing time: 12.83 hrs
Weekdays only: 18 days (3 1/2 weeks)*
Weekends only: 2 1/2*
Streaming on: Netflix, Hulu+ (Seasons 1-2)
The Hills 2.0 show also features PR mogul Kelly Cutrone.
*Four episodes per weeknight or 16 per weekend.
4. Dawson's Creek

Seasons: 1-6
Episodes: 128
Total viewing time: 89.6 hrs
Weekdays only: 64 days (13 weeks)
Weekends only: 16
Streaming on: Netflix
5. Felicity

Seasons: 1-4
Episodes: 84
Total viewing time: 58.8 hrs
Weekdays only: 42 days (8 1/2 weeks)
Weekends only: 10 1/2
Streaming on: Netflix
Pro-tip: If you are famous for your hair then don't cut it all off. When it goes, the show goes.
6. Friday Night Lights

Seasons: 1-5
Episodes: 76
Total viewing time: 53.2 hrs
Weekdays only: 38 days (7 1/2 weeks)
Weekends only: 9 1/2
Streaming on: Netflix, Hulu+ (Seasons 4-5)
7. Greek

Seasons: 1-6
Episodes: 74
Total viewing time: 51.8 hrs
Weekdays only: 37 days (7 1/2 weeks)
Weekends only: 9 1/2
Streaming on: Netflix
Lead actress, Spencer Grammer, is Kelsey Grammer's daughter.
8. The Hills

Seasons: 1-6
Episodes: 102
Total viewing time: 37.4 hrs
Weekdays only: 26 days (5 1/2 weeks)*
Weekends only: 6 1/2*
Streaming on: Netflix, Hulu+ (Seasons 1-3)
Famous for introducing the world to Speidi.
*Four episodes per weeknight or 16 per weekend.
9. Jack & Bobby

Seasons: 1
Episodes: 20
Total viewing time: 14 hrs
Weekdays only: 10 days (2 weeks)
Weekends only: 2 1/2
Streaming on: TheWB.com
Oh look, there is Roger Sterling and Megan Draper before they were Mad Men-famous.
10. Laguna Beach

Seasons: 1-3
Episodes: 45
Total viewing time: 16.5 hrs
Weekdays only: 12 days (2 1/2 weeks)*
Weekends only: 3*
Streaming on: Netflix (Season 1), Hulu+
The story of The Hill's LC before she moved to the big city.
*Four episodes per weeknight or 16 per weekend.
11. Melrose Place (Original Series)

Seasons: 1-7
Episodes: 226
Total viewing time: 158.2 hrs
Weekdays only: 113 days (22 1/2 weeks)
Weekends only: 29
Streaming on: Netflix
A role on Melrose Place was a prerequisite to starring on Desperate Housewives.
12. Melrose Place 2.0

Seasons: 1
Episodes: 18
Total viewing time: 12.6
Weekdays only: 9 days (2 weeks)
Weekends only: 2 1/2
Streaming on: Netflix
The show stars Ashlee Simpson when she was still known as Ashlee Simpson-Wentz.
13. My So-Called Life

Seasons: 1
Episodes: 19
Total viewing time: 13.3 hrs
Weekdays only: 10 days (2 weeks)
Weekends only: 2 1/2
Streaming on: Netflix, Hulu
Claire Danes is also famous for her Latisse commercials.
14. The O.C.

Seasons: 1
Episodes: 27
Total viewing time: 18 hrs
Weekdays only: 14 days (3 weeks)
Weekends only: 3 1/2
Streaming on: TheWB.com
15. One Tree Hill

Seasons: 1-8
Episodes: 174
Total viewing time: 121.8 hrs
Weekdays only: 87 days (17 1/2 weeks)
Weekends only: 22
Streaming on: Netflix
Hilarie Burton was also a host of MTV's Total Request Live.
16. Roswell

Seasons: 1-3
Episodes: 61
Total viewing time: 42.7 hrs
Weekdays only: 31 days (6 1/2 weeks)
Weekends only: 8
Streaming on: Netflix
Everyone got their start on Roswell, including Emilie de Ravin (Lost), Colin Hanks and Katherine Heigl (Grey's Anatomy).
17. Skins (UK version)

Seasons: 1-6
Episodes: 55
Total viewing time: 38.5 hrs
Weekdays only: 28 days (5 1/2 weeks)
Weekends only: 7
Streaming on: Netflix (Seasons 1-5), Hulu (Seasons 1-6)
The original (and best) series that MTV tried to ruin.
18. Sweet Valley High

Seasons: 1
Episodes: 22
Total viewing time: 15.4 hrs
Weekdays only: 11 days (2 1/2 weeks)
Weekends only: 2 1/2
Streaming on: Netflix
19. Undressed

Seasons: 1
Episodes: 30
Total viewing time: 11 hrs
Weekdays only: 8 days (1 1/2 weeks)*
Weekends only: 2*
Streaming on: Undressedtv.com
Notable cast members include Christina Hendricks, Adam Brody and Sam Page (Greek, Mad Men).
*Four episodes per weeknight or 16 per weekend.
20. Veronica Mars

Seasons: 2-3
Episodes: 42
Total viewing time: 29.4 hrs
Weekdays only: 21 days (4 1/2 weeks)
Weekends only: 5 1/2
Streaming on: TheWB.com
Ryan Hansen would later star in the Starz cult hit, Party Down.
21. The Wonder Years

Seasons: 1-6
Episodes: 115
Total viewing time: 42.2 hrs
Weekdays only: 29 days (6 weeks)*
Weekends only: 7 1/2*
Streaming on: Netflix
*Four episodes per weeknight or 16 per weekend.