What TV show can I engross myself in after I finish Buffy the Vampire Slayer?

I need to fill the wee hours of the nights somehow, and Buffy has been it for the past several months. (Oh, how I love it!)

I’ve never had TV so I’m not up on many shows except those I’ve sought out on DVD. Any suggestions?

As a frame of reference, I also love Freaks and Geeks, My So Called Life, and The Office.