One of my favorite topics is analyzing feminist themes on television, as well as gender portrayals of both male and female characters. Having just marathoned the entire Felicity series this summer, some of my thoughts about feminism, gender roles, and relationship equality within that particular show can be found here (with an expanded version here).
Also, a couple related links that caught my eye:
Although everyone's list of this type would probably be different, I thought three notable absences from these were Clair Huxtable from The Cosby Show (& probably Sondra too), Maggie O'Connell from Northern Exposure, and Elaine Benes from Seinfeld. Who would you add?