All those serial killer/slasher films have never been able to do it for me.

What are some of the best films to be released in this genre?

District 9
Moon
The Matrix
Back to the future
Alien / Aliens
Terminator 1 & 2
12 Monkeys
Star Wars Original Trilogy
Original Planet of the apes........
So many fantastic sci fi movies,

Poltergeist
The Thing
The Fly
The Shining
The Exorcist

I won't bother posting the classics or the obvious.
Pandorum
Altered
Alien Raiders
The Thaw
Slither
Pitch Black
The Signal
The Objective
to start

A few great sci fi movies are:
Stalker (1979)
Solyaris (1976)
Slaughterhouse-Five (1972)
Stalker and Solyaris are Russian and very slow, but very good if you give them the chance.
You say serial killer flicks don't do it for you, but have you seen Angst (1983)? To me, that one is the best and miles ahead of it's time.

Yet again you come through, Watch Pandorum last night thanks to a post of yours and loved it!
Also a massive fan of Pitch Black! Though yeah the classic of course ive seen.

Slither i thought was pretty silly, Decent plot and cast but coulda been alot better.

Yea, Slither was supposed to be silly. It was a throwback to older scifi/horror films of the sixties and seventies. B movies. Was fun though and had cool creatures.

Best Sci-Fi:
Inception