A lot of this stuff I only noticed after the first season had begun airing (thank you quick dvd sets), usually because of buzz in places like this:

Battlestar Galactica (didn't have Sci Fi at the time, and even if I did I wouldn't watch this out of order)

Friday Night Lights (they did an incredible job getting this released as a dvd set before season 2 started and at a great price, even if they had to lose some of the music... Still, I would've never picked this up if not for this forum)

Gilmore Girls (didn't start until after I got married, which removes the shame from owning every season on dvd... somewhat)

The Office (American)

Survivor (only watched it off and on the first season)

Sounds like how I got into NYPD Blue. Was too lazy to find the remote control after The Pretender rerun on TNT ended, so I ended up having Blue on as background noise. Eventually I said "wow, this is a pretty good show," and started watching it.

Turned out that TNT aired it once in the morning and once in the evening, and Court TV had 2 airings a day as well... and they were all from different seasons! I was unemployed at the time, and got caught up on the entire series in a space of a couple of months.

Buffy the Vampire Slayer
24
Boston Legal

Gilmore Girls
How I Met Your Mother
The Office
Scrubs

The Sopranos (age)
Arrested Development
The Office
Freaks and Geeks
Undeclared
Entourage
Weeds
My Name Is Earl
30 Rock
It's Always Sunny in Philadelphia
South Park
Family Guy

damn, I don't think I've watched any shows I like from the start. Almost all of those were word of mouth recommendations where I rented the DVDs except Family Guy and South Park.