Edgar Rice Burrough's John Carter of Mars books are high on fantasy elements, but are they sci-fi?
If you think about it, why are "Dune" and "Hitchhiker's Guide to the Galaxy" in the same list? They are totally different types of books. The list can be split up many, many ways.
In fact, if you prefer the science fiction side of the genre, you might try what I've finally found to be the case: they're still producing a lot more fine science fiction across the pond in the UK. Some of this makes its way to bookshops in the US, but not all, and the titles that do get published over here generally come out six months to a year after the UK release. That's also a consideration if you're a collector of HB 1st Editions - for UK authors, the 1st is almost always the UK edition.
UK editions can be ordered from www.amazon.co.uk. It's a little more expensive with shipping as opposed to waiting for the US edition, but with some authors the US edition never appears or appears only in paperback some years later.
Check out Alastair Reynolds for outstanding space opera set thousands of years in the future (start with the first, the excellent Revelation Space); ditto Paul McAuley and Ian McLeod. All three are eventually published stateside. Not so often making it to our shores but worth checking out: Adam Roberts, John Meaney, and Roger Levy. Some of these last also waste their time on fantasy.
And if you must do fantasy, you might check out Justina Robson, Steph Swainston and, of course, China Mieville.
And my personal favorite: Neal Asher, a prolific SciFi writer tilted toward the military SciFi end of the spectrum - and a writer with a distinctly libertarian bent, you'll learn if you read his blog: http://theskinner.blogspot.com/ A quote from a post a few weeks ago after the shuttle's last landing ...
Well, the last ever US shuttle mission is drawing to an end. I wonder how long itll be before the space station is abandoned whilst politicians on Earth concentrate on such critical occupations like bombing Arabs, wasting money on windmills, buying off large numbers of those who vote for them by employing them in pointless bureaucracies, taxing businesses to extinction whilst pocketing huge salaries and expense claims and growing increasingly disconnected from reality by their perception of how important they are.
Couldn't have said it better myself.