I hadn't heard of Float Out going to have to check that out.
Buffy and Leverage would by my top suggestions for you. And if you are ready to dive deeper into sci-fi then Farscape would be right up your ally; Incredible characters with some of the best development of any show ever, great relationships, a good mix of comedy, drama, and action. The only reason I don't immediately recommend it is that it is full Sci-fi; aliens, crazy tech, weird sciecne, the whole shebang. But if you are considering Dr. Who then you are probably okay with that.
So a couple of things to discuss now that you have seen everything in Firefly. I remember you asked after Out of Gas why the crew came back, here's my thoughts. On one shuttle you have Zoe, Wash, Simon, and River. Zoe is practical and Simon is smart, they know their chances of stumbling on to someone in space are slim to none. Zoe is not about to let them abandon Mal to die alone for some false hope. Plus you have River and her psychic instincts who might have known it was safe to go back. On the other shuttle you have Inara (pilot), Kaylee, Jayne, Book. Jayne will want to continue, Book will probably be good either way. Inara cares about Mal and won't want him to die alone, plus (and I don't know if you picked up on this) she has no issue with dying. She has a suicide kit in her room and there are some prominent theories that she is already dying, so she will want to go back to Serenity. Finally you have Kaylee who A) views Mal like a father and B) truly loves Serenity. If she thinks she is dead either way she would certainly choose to die on Serenity. Book would go along with them and even Jayne wouldn't be able to stop them then (especially with Inara piloting).
Second topic. The Message really shows why I don't like the Kaylee/Simon relationship. I feel like it is just a relationship of convenience. They are both young, attractive, and very single. There are no other options around (and Kaylee's flashbacks plus comments make it clear how desperate she is for "companionship") so they flirt and get together. Hence Tracy shows up and Kaylee is quick to switch her attentions to him instead of Simon. I really feel like that relationship lasts only as long as no better candidates are around.
--
(Maniac64 at work) [Browncoat] ~Board 570901~
All the proteins, vitamins, and carbs of your grandma's best turkey dinner, plus 15% alcohol.