If you are looking for something still on the air now--I don't think there is much of anything worth watching in sff.
The Vampire Diaries all angst all the time with no interesting plotlines or characters anymore.
Supernatural jumped the shark after S5 and has turned into a joke with repetitve angst, lame recycled plots and ever more increasing campiness replacing its once solid dramatic gravitas.
Fringe is not very good. It is a pale imitator of the much superior The X-Files. The only interesting thing about it is the mythology but by season 3 and 4 they've revealed that the writers have very lame ideas on how to pay it off so ultimately it is a waste of time.
Actually while we've had a lot of sff shows in the last ten years sitting here I realize just how 99% of them were crap so I'll save you from wasting your time--V, Flash Forward, Persons Unknown, The Gates, The Event, Stargate Atlantis, Caprica, Stargate Universe, Surface, Invasion, Bionic Woman, Knight Rider, Fringe, Flash Gordon, Terra Nova, Falling Skies, Haven, Eureka, Warehouse 13 Alcatraz, post S1 Heroes to name a few.
And if you are wanting recommendations from the last decade I'd recommend for sff seasons more than actual series since I've personally found the days of a consistently entertaining series with a good 3-4 year run of episodes has become a thing of the past and it is best to cherry pick-
I'd recommend
ENT's third season but only the arc heavy episodes--half of the season was uninteresting filler.
Heroes S1--in my opinion the single best season of tv in the last decade--heavily serialized with no real filler to speak of, every episode focused exclusively on the arcs, no dragging out answers like LOST tended to, the season always advanced the story with no spinning wheels, likeable if not deep characters--an absolute thrill ride with no bad episodes which is astonishing given it had a 24 episode order. After S1 the series became unfocused and instead of focusing on a few interesting ideas and developing over the course of the season the writers began throwing evey idea at the screen then almost instantly deciding to dump them and moving onto the next one.
I'd only recommend LOST S1, S4 and S5 but you'll probably want to watch S2, S3 and S6 since there is a lot of information you need for what is to come but S2 was a total bore, S3 was stalled for half the year before picking up and the last season was awful with no satisfying resolution.
Supernatural S1(more episodic with a light arc think X-Files early one, things are more laid back the calm before the coming storm), 2 and 4(the best plotted season of the serie)s are pretty good--S3 is uneven and overall pretty weak. S6 and S7 avoid
Jericho S1 and 2= entire series--good cast, good storyline
nBSG S1 and first half of S2.