I don't watch a lot of TV series, because I'm frequently not home in the evenings, and it gets hard to catch up and the DVR just gets used up. But I have enjoyed The Good Wife this season, as well as some episodes of Glee. I started watching Lost just last season, and I'm looking forward to that starting up again soon. I tried watching a few episodes of Flash Forward this year, but that doesn't really do it for me. Oh, and I've watched some Mad Men, too, which I really like.
The show I haven't seen at all that I think I want to check out is Dexter. I suppose the best way is to get the season 1 DVD and start from there.