Interstellar is a great movie. There are some huge, glaring holes/issues with parts of the plot (you'll see what I mean) but it's otherwise pretty smart and ambitious - what you expect from Christopher Nolan.
I'll throw in Darren Aronofsky's 'The Fountain' as another smart, ambitious sci-fi move that sort of collapses under it's own intellectual weight, but is very good with an amazing score (Clint Mansell) and awesome performances from Hugh Jackman and Rachel Weisz.
Most recently, I loved 'Ex Machina' - smart, scary take on AI.
EDIT: Will add two more indie sci-fi flicks from director/actor Shane Carruth - mindbending time travel movie 'Primer' and, I actually have no category for this film, 'Upstream Color'. Maybe the most interesting writer/director working in film today.