I can tell you, I don't think I've ever obsessed over a T.V. series, that is until I watched Firefly. Farscape was neat, but I could do without. Same with Sliders and Stargate and other similar Sci-Fi shows. But Firefly is friggin amazing.
The show is a Sci-Fi Western. I've really developed a connection to each and every one of the characters.
A brief run-through of the characters:
Mal - the captain. Definately has some of the best lines. Nathan Fillion does a most excellent job of portraying this character as he sould be.
Zoe - Mal's old army buddy. She's married to Wash. Mal's second-in-command. Her relationship with her husband provides for some interesting moments.
Wash - the pilot of the ship. He's not a fighter, though does envy Mal's and Zoe's army-buddy relationship.
Kaylee - the ship's mechanic, played by Jewel Staite. I don't know why, but I think she's incredibly pretty. A very homely girl that knows the workings of machines.
Jayne - at first glance, a seemingly flat character. However, one episode provides so much character development for him that it's wild.
Inara - a "companion." Her relationship with Mal is one of interest in the series. Lots of tension between those two.
Book - a "shepherd." Basically, a preacher. The conscience of the group.
Simon - the medic of the group. A rich kid that left his life to save his sister. His character is very deeply developed throughout the series.
River - Simon's sister. Definately the most interesting and sporadic character. I can't really say more without giving away too much plot.
Serenity - the ship. The crew's home and workplace.
Anyway, I have really fallen in love with this series. It's very dramatic at time, it's very funny at times without being stupid, and it's great overall. If you watch the DVD extras, you'll see that they used some cheesy camera moves, but it works very very well for this style of series.
Edit: oh, one last thing. Space is treated exactly as space should be treated in this series. The laws of physics hold true in Firefly.
On Amazon:
http://www.amazon.com/exec/obidos/tg/detail/-/B0000AQS0F/qid=1094625168/sr=8-1/ref=pd_ka_1/104-1851280-1134322?v=glance&s=dvd&n=507846