Shamelessly stealing Rob’s post, here’s a rundown of what I’m watching at the moment, apart from the few breaks I take to study 
Heroes – I loved the first season, I haven’t yet watched the first episode of the second.
Battlestar Galactica – As Rob says, what a cliffhanger at the end of the third season! Looking forward to Razor.
Californication – A very amusing David Duchovny plays a heavy drinking, heavy smoking writer who sleeps around a lot and wrestles with an uneasy relationship with his ex-wife, his daughter and is various other friends. Very funny, worth checking it out.
Studio 60 – This comes from the genius behind West Wing, Aaron Sorkin. Unfortunately, it was cancelled after the first season, but it’s well worth a watch.
Grey’s Anatomy – Lost touch with this at the end of season 3, so I’m going to need to recap before starting on the next.
House – The hilarious Hugh Laurie just gets better and better in this, currently watching season 3.
Prison Break – The first season was incredible, the second season mixed, the opening episode of the third season has neatly extended the plot line sufficiently. I’ll reserve judgement on the new direction!
Apart from these regulars, I’m looking forward to checking out Jericho and Criminal Minds. I also am sorely missing Veronica Mars so might check out ‘Chuck’ as Rob suggests.
Jericho is well worth the investment. That said season one doesn’t really provide satisfaction with the final episode. They were talking about making another 4 episodes after the “nuts” campaign but I’ve not heard anything recently.
Will check Californication – sounds intriguing!