Angst? What Angst?: Played with in the pilot in regards to Brisco not seeming too broken up by his father's death. He reasons that with the old man a lifelong lawman, he had a very long time to prepare for him dying on the job. However, at the much later graveyard scene, Brisco is clearly in mourning and regrets not resolving their problematic relationship. Later episodes show that while he maintains his professionalism, Brisco doesn't take his father's death lightly and still misses him.
Awesome Music: Randy Edelman's theme music (as well as his score for the Pilot Movie). NBC sure thought it was awesome: when Edelman threw it into a portfolio he sent them when being commissioned for a new NFL theme song, NBC producers liked it so much that they used it during marquee Major League Baseball games, and more prominently, as part of its traditional soundtrack for the Olympic Games (typically on the "coming up tomorrow" segments).
Ensemble Darkhorse: Pete Hutter was meant to be killed in the pilot, but Boam and Cuse were so impressed with the actor that it became a recurring role, complete with Running Gag of surviving in very unlikely circumstances.
Dixie Cousins very much so. She was always intended to be a recurring character (unlike Pete), but as part of a Love Triangle with Brisco having to decide between her and Amanda Wickwire. However, the actress made such an impression in the Pilot Movie that the writers altered their plans to retain only Dixie as a Love Interest.
Professor Wickwire. A nice, quirky borderline-Mad Scientist, who - unlike his daughter - was retained from the pilot to be a recurring character. Helps that he's played by John Astin, too.
Sheriff Aaron Viva may qualify, as he originally made a one-off guest appearance only to then play a major role in the two-part finale.
Friendly Fandoms: With Firefly, due to both being fusions of westerns and sci-fi. They even share a prop, as Bowler's sawed-off shotgun became Zoe's.
"Funny Aneurysm" Moment: At the end of "High Treason, Part 2," there is talk of further adventures for Brisco and Lord Bowler, but Bowler stresses "after a hiatus" first. The episode was shot as a season finale (hence the hiatus joke), but the series was cancelled over the summer break.
He Really Can Act: Let's face it, Bruce Campbell is one of those actors who really needs to do nothing more than be himself to get the audience invested. But a few scenes in this show, like Brisco's visit to his father's grave at the end of the pilot, show that he really can be an effective dramatic actor when he wants.