Awhile ago SFSignal looked at the current state of SF TV and they discussed what they thought of several different SF shows. The U.S. Spring television season has just come to an end (and what a vast wasteland of nothingness we are in right now) and with it, several of those SF shows gave us their last, best shot until next year (or never again).
A quick look at the earlier article shows us several shows that either haven't ended their current run yet (Stargate Universe) or haven't started their 'summer' season, thanks to SyFy's bizarre scheduling (Eureka, Warehouse 13). But all of the big network shows have ended, one way or another, and it's those SFSignal will look at. One quick administrative note: Heroes has been canned and it's about damn time and about three seasons too late. Still, when you're NBC, you don't have much else to fall back on.