From the list:
Lost
Battlestar Galactica (new)
The X-Files
Doctor Who
Terminator: The Sarah Connor Chronicles
The Twilight Zone (original)
The Outer Limits (new - because I've never seen the old one)
Heroes (though it is not really a good show, to be honest...)
Buffy (but that's not exactly SF, is it?)
Fringe (well, I've only started watching it, so I wouldn't exactly say "I love it", but I like it)
Futurama (but I didn't notice it in the poll so I did not tick the box)
other:
The 4400
Space: Above and Beyond
Red Dwarf
Babylon 5 (though I've just started watching - but I liked what I've seen so far)
Caprica (the pilot rocked)
La Femme Nikita (it is Spy-Fy, definitely had a lot of SF elements)
Torchwood (more 'like' than 'love')
Kyle XY
The Visitor
Ray Bradbury's Theater
(I liked The Planet of Apes as a child - as well as the old BSG.)
Other people have mentioned shows like Twin Peaks and Carnivale. They're not SF by any means. But if we're counting fantasy/dark fantasy/whatever the hell it is called, I will add:
Twin Peaks
Carnivale
Millennium
and a very special place in my heart is reserved for a very obscure cult UK series called Night and Day (very Twin-Peaksish, but even more bizarre and surreal, although it only occasionally had elements of fantasy).