Okay, I'll admit it. There are only four shows I actually watch on television anymore, and three of them are on SciFi.
Both Stargate SG-1 and Stargate Atlantis have consistently good writing and well-developed characters. Watching them is like curling up with a favorite book or visiting old friends.
Battlestar Galactica is unlike any other show I've ever seen. It's always startling, emotionally real, and courageous enough to go to the darkest places in the human heart and mind. This is a show that will rip you to pieces one minute and leave you with unexpected hope the next.
And yes, I thoroughly enjoy watching Firefly, which we have on DVD. Despite being cancelled after less than a full first season, this show was so wildly popular with fans that the creator, Joss Whedon, was able to produce the theatrical movie Serenity on the basis of their support. Check out the show and the movie, and you'll know why the fans just can't let these characters go.