I loved Firefly. Too bad it didn't last longer. Fox only aired about 6-7 episodes and aired them out of sequence. They played the 2nd epi first, and the pilot was the last aired. Don't ask, I have no idea why. Anyway, enjoy. It's excellent.
I watched it in its original airing, on USA or whatever, then again in the (I think) SciFi rebroadcast, and I have the DVD set, with Whedon's commentaries.
According to Whedon, the 2nd scripted/filmed episode, "The Train Job", became the first episode aired after the initial network viewed/accepted the pilot, after it was mostly scripted but before it was filmed. The network was concerned that they needed to hook an initial audience with a higher action story, rather than all the careful setup, background color, and teaser mystery that was the basis of the pilot. Because the change in sequence came before the shooting, Joss was able to insert a modicum of essential background material, but he and the network schedulers then had to find a slot to insert the pilot with its fuller set up story. I think in the initial airing it came third, but I could be wrong.
There are 11 filmed episodes, 2 of which were not broadcast in the initial run.
Though subsequent airings on network and local TV maintaned the same order of airing (I never heard of the pilot being last, though), when the DVD set was prepared/ released, Joss rearranged and re-edited back to the originally concieved order of play.
Incidentally, the Firefly DvD collection set some kind of DVD industry record in the first year of its release. I think it was the largest number of a single-season show ever actually PURCHASED (vs rental, etc) in the year of its release. Whedon credits the success of the DVD set in large part with stimulating the backing and studio interest that allowed the movie to be made.
Don't hold your breath for more Firefly. Whedon has said in post-movie interview that though he still loved the Firefly concept as some of his best work, he was reasonably satisfied with having been able to do the movie and take the story to better closure. If the movie was successful enough to stimulate interest in a sequel form, movie or mini-series fairly quickly, he would consider it, but he was not going to put the rather major effort into keeping it alive that he did between the end of the series and the go-ahead decision for the movie. He also was not attempting to keep the cast on retainer beyond a short period following the movie, as it was too limiting on them and too expensive for him with such a big pool of talent. In the event - the movie did "reasonable" in theater release but about 10-15% below what the producers had hoped for in initial run. It did not stimulate any immediate interest in a further sequel project among the producers/backers, and Joss himself said that he had several other projects that he needed to spend time on. Note that there is further evidence of this in that several key members of the cast, notably Zoe and Callie, are in long term commitments to other shows.
drrider