The Cryptonomicon – Neil StephensonEvery book Stephenson writes seems to be better than the one before, I loved Snowcrash, really like The Diamond Age and this is better than both of them. Some people think he gets a bit verbose at times, but I actually enjoy those bits! The Baroque Cycle is even better again, but I'm not sure it's really Sci-Fi in the sense I mean.
Neuromancer – William GibsonThough I like some of his later books better, this one is a classic. It was the first science fiction book I ever read and is therefore the reason for the rest of this list :)
Diaspora – Greg EganEgan's books are wonderfully detailed, sort of like physics textbooks but interesting. The impressive thing is that the plot seems to fall out naturally from the science. I could have picked any of his books, they are of such consistent quality.
Holy Fire – Bruce SterlingAnother author I really like, this book doesn't seem to get talked about as much as some of his other work but I found the idea behind this one to be extrememly interesting: as people live longer and those who live longer tend to be the people who are more risk averse, society becomes increasingly conservative.
Fallen Dragon – Peter F HamiltonThere's nothing like clutching a very thick paperback, and Hamilton is responsible for quite a large number of very thick books. Although I enjoy those, this shorter, stand alone novel is the one I like the best.
The Algebraist – Iain M BanksBanks' early science fiction novels were really great, they tailed off somewhat (though were still very good) but I felt this novel is something of a return to form. An interesting and unusual universe, weird aliens, and an almost whodunnit like plot.
Hard Boiled Wonderland and the End of the World – Haruki MurakamiI really love Murakami, he's only written one Sci-Fi book and it's the first novel of his I read. Not much for the hard science, but enough off-beat and plain weirdness to keep everyone interested.
Green Mars – Kim Stanley RobinsonReally I like this whole series, I just arbitrarily picked the middle one :)
Elvissey – Jack WomackIt's not often that science fiction books invent a new dialect of English (it's more of a fantasy thing, I think), once you've deciphered the dialogue this is a great novel, the terror of the rise of scientology is set against an Elvis from an alternative universe.
Spares – Michael Marshall SmithNot so much in the hard science vein, but Smith is a very witty and imaginative writer.
OK, so really what this section means is I couldn't limit myself to just ten books...
Vurt – Jeff NoonThe Winter Queen – Joan VingeLearning the World – Ken MacLeodWetware – Rudy RuckerFirestar – Michael FlynnWoken Furies – Richard MorganSea of Silver Light – Tad WilliamsDarwins Radio – Greg BearRed Dust – Paul McAuleyJennifer Government – Max BarryPlease see Robs Top Tens for a general description of the criteria and reasons for exclusions.