I want more Stargate. Don't care which one they do. Atlantis would be nice since they never finished that story. 

Also, I love the other suggestions in this thread. Especially Dresden Files and Sliders. Sliders could be a little campy sometimes but alternate history is fun. The one that sticks out for me was the one where the American revolution never happened. 

Omg, I just noticed rumrunner815 suggested firefly and buffy. Yes, both of those but especially the latter. Too many people in firefly are dead either in universe or irl. Like could you have a proper firefly show without wash? Since he died in the movie. (spoiler alert?) Buffy though... So much potential there...

Stargate is one of my favorite shows settings and Atlantis I would love to see more of or at least a continuation seeing as there were only 5 seasons of it. Stargate Universe would be nice to see as well cause there were only a few seasons of that and they left a HUGE hanger when it comes to the last episode.

The Dresden Files would be an amazing show to continue or reboot. The storyline was great as well as each episode, I don't know how they would continue it, maybe add a new character that is able to do magic and Dresden is the teacher or something I have no idea. I have seen that show 2-3 times.

Defiance was a good show too but had its flaws when it came to the video game that almost made it but the player-base was not there at all once the show continued and then stopped. If it continued and players got exclusive things that the show had I am sure that game would have worked out.

Heros, I think that the show really should have been more and not a spinoff that in my opinion was good but I think that they should have really stuck with the main characters of the show instead of adding more characters to the spinoff.

Leverage, this show was great and it would have been amazing to see it continue. Sadly one of them went off to play in Supernatural (Mr. Crowley) and another went to play in The Librarians (Jacob Stone).

Jericho, a post-nuclear show that happens to be a good story, in my opinion, I think they ended it odd or just to fast of an ending.

V, I have not seen enough of the show to really have an opinion but it would be cool to see more of it. It was a cool Syfy aspect and whatnot.

One show that really NEEDS more episodes and that is...

HANNIBAL!

GIVE US S4 ALREADY!

Deadwood, they didn't give us much of an ending.

We needed more Sopranos than what they made and now it's too late with Gandolfini no longer with us.  Next the Game of Thrones is about to end....we definitely need more!

OH! Also, I'd like to see them get rid of that dumb teen titans go and go back to the way it used to be drawn and the darker story lines. That was a solid show.

New Episodes of Futurama, please!

Burn Notice was good entertainment.  I could stand a few more seasons of that.

The O.C.  yes the second season was terrible but the 1st and 3rd were great!

Boogie - There is going to be a second season of Limitless its just on hold I think, I have not looked into it in the last few months but that is what I read about the show. I can not wait to see if there is going to be another season of the show.

Burn Notice - Great show, I think that I still need to finish it but lost my Netflix about 4-5 months ago and I plan to get it back soon.

Theres a couple shows I'd love to see more from.  Either they got canceled too early or just got pushed out by something else.

Pushing Daisys

Dead Like Me

Lie to Me

Limitless (TV)

I loved all of these shows, but they ended unsatisfactorily or got canceled without a proper ending. I'd love another season of each of these, just to finish off most of them properly.  

The Sopranos but unfortunately if they did this then it would never be the same again :(

Rest in peace James Gandolfini <3

Quite recently I finished Black Sails, which pirate theme I absolutely digged. But well, it's finished, but I wouldn't mind more time with that cast.

All in all I think the pirate genre is somewhat underdeveloped (apart from the obvious franchise), but I guess the setting comes with obvious production costs.

A show that was cancelled called Revolution. I miss that show

Oh man. I'm so upset that they decided to cancel The Lazarus Project. One of the best shows in recent times in my opinion. 

It might be a stretch, but I’ve always thought The Truman Show could have an amazing sequel, as long as it’s made with the same passion as the original. People usually get upset when I say that, though.