Assuming there was a time warp and the shows could pick up exactly where they left off (no accounting for actors aging, etc.) and damn, past no. 1, this is a hard choice.
1. Profit (The best

ing thing that ever has and most likely ever will be put on television, especially in the US)
2. Star Trek: The Next Generation (Yes, I know it lasted 7 seasons, but it still had legs. It should have never been cancelled.)
3. Nothing Sacred (Doomed from the start, but truely one of the most soulful [no pun intended] shows ever made.)
Honorable mentions: C16, Strange Luck, VR5, Partners, the other damn Jon Cryer show that lasted half a season that I can never remember the name of, Cracker (US version), My So-Called Life, life as we know it, Forever Knight, The Dungeons and Dragons cartoon, Harsh Realm, Sledge Hammer, The Prisoner, Monty Python's Flying Circus, Brisco County Jr., The Tick (live action) [Yes, I am aware that a couple of these actually ran their course and weren't cancelled, but, dammit, I want more episodes]
And yes, if DB Sweeny is in something, it's doomed, unfortunately. At least Jon Cryer kicked his curse.
I would have listed Firefly, but if Serenity was the future course of the show, it really should have stayed dead.