I love Firefly !
Its one the best scifi for TV ever made. Beeing a scifi fan in general you have to put up with alot of crap. Almost anything with sci-fi in it is targeted at 13yr olds.
Firefly feels realistic in a humerous way! No silly looking aliens or meaningless tech-talk like in startrek.
I really like the fact that they are just a small pirate ship with a small crew, sneaking from one half-legal job to the next. Still when the series ends you are beginning to get this feeling that they are in a universe that is alive outside the screen.
All this and the fact that Josh is the master of character development
I really like buffy alot too, not season one though.