In addition to the various Trek series and movies, the failed spin-off pilots, the Roddenberry legacy shows like Earth: Final Conflict and Andromeda, there are many other related series, documentaries, and movies that play right into the Star Trek Channel idea.
Some others mentioned B5 and related shows/movies, but then there are also all of the fan films, which, though perhaps non-canonical, could be shown with disclaimers and the makers of the works of love could benefit from their hard work.
I can envision several real-time memorabilia shows, a la QVC and HSN where stars, writers, and producers can cash-in on things they saved from years of work.
I would encourage Paramount to consider the Vulcan concept of I.D.I.C. in creating this network, and also, HIRE ME TO CONSULT.
I am a big Trekker at heart, but I can also take a step back and recognize the need to appeal to non-Trekkers as well. I believe this can be done.
Shatner can re-vamp his talk show (loved it!) and Nimoy can re-launch In Search Of, both the classic episodes and a "Next-gen" version.
Anything and everything even vaguely Star Trek related can be considered.
Above all, the highest recommendation I can provide is...make it as interactive as you can while still keeping it Trek.