I dunno about sci fi, but there are some good fiction books out there that are enjoyable that border on it. I always forget if his name is "McCammon" or "McGammon" cause it's been a while, but Swan Song by Robert Mc[G/C]ammon is really good. If you've ever read any Stephen King, it's best described as "What 'The Stand' SHOULD have been." The world gets devastated by a nuclear war, and then all hell breaks loose. AWESOME book. Also by Mc[G/C]ammon is a book called "They Thirst," which is about vampires obviously, but I have yet to read it. My friend says it kicks ass, though.
If you want fantastic and farfetched stuff, the Dark Tower books by King will keep you occupied for a long time. Taking place in a post-apocalyptic world, where time and space itself seems to be collapsing, it borders on fantasy/sci-fi hybrid more than anything else.
[[DT bends over LOTR and mercilessly pounds it in the ass, for the record!! :0) hehe ]]
Heinlein is the only classic sci-fi writer that doesn't aggravate me, but that's a personal thing. Just be prepared for some disappointment if you read classic sci fi, cause chances are someone's adapted the story into a better book or movie as far as the immersiveness of the experience goes. Brave New World and 1984, for instance, were both utter crap compared to the sci-fi channel's remakes of both. Another good example is Starship Troopers by Heinlein. A great read, but be prepared for illogical differences from the movies we know in our days (the bugs talk and carry guns like people...little convoluted? Or maybe the movie's producers were jonesing to be the next "Aliens," heheh). Asimov's books are pretty decent--I didn't like his writing, but his ideas are good.
STAY AWAY FROM L. RON HUBBARD.
There is always Dune, which is considered the LOTR of sci-fi. I have a friend who loves Dune, but thankfully, Dune fans aren't nearly as annoying and full of themselves as LOTR fans, so you can decide based on that. I've never read it but it is considered to be a semi-legendary piece of sci fi lit, and I haven't really heard anyone who's taken the effort to read it complain much.
And if you're in the mood for some humor...the Douglas Adams books are pretty entertaining, in a campy, british way that most people enjoy. My friend called it "Literary Monty Python on acid" once. Hehe.