Firstly, oh my god this is hard! Five isn't enough! I just hope the rest of my books somehow float my way.
Ok. My five, based on re-readabilty, memories and keeping my sanity whilst I survive on Coconut Vodka and Banana Daiquiris:
1) The Hitchhikers Guide to the Galaxy. Ironic, Witty, Hilarious, Genius. A book and a tale I have read and listenned to for many years wrote by a man who once shook my hand and made me very nearly find religion, though perhaps not the kind that Pope dude would enjoy! I have read the entire series so many times I cannot count the number and it is the #1 choice for me if stuck on a desert island.
2) Ender's Game. Some love it, some hate it. I adore it and find the personalities and social ingenuity involved, brilliant. Like all the books here, it make my brain come alive and see IMAX in my head. I first read it fairly recently, Emma had it and I'd heard of it but never read it. Then I moved to her place and slowly worked my way around her bookcase and found, for me, and instant classic.
3) Gridlinked. Has to be that one. I love Cowl, I love The Skinner and the rest but to me Gridlinked is the best. It was my introduction to Neal and was right down my alley with its license to kill Agent Cormac. A thrill ride all the way with enough sub plots and twists to make me read over and over. This one I would read when I started to feel my first dose of apathy, to kick start me back into surviving.
4) Battlefield Earth. I know, I know, and I do not care. The author was a complete nut job, this is now certain. The writing isn't even that good and is very simplistic and child like in parts but its one of the first 'proper' Sci-Fi books I read as I got older and I fucking love it. In my opinion only the Revelation Space series has come close to the epic scope of humanity this book offers. Everytime I read it my childhood comes back and I dream of Flash Gordon.
5) Jonathan Strange and Mr Norrell. The GF hates this book, with a passion, one that I cannot understand. In terms of writing this is, to me, the best book I have ever read. The alternate past in which it lives is one I dearly wish was the real one. I don't tend to enjoy 'fantasy' books but then again I don't rate this as fantasy. Its about magic, yes, but more than that, its about the Magicians and once I pick this up I cannot fail to read from the miniscule starts to the fatalistic ends of the key characters. My only regret is that Susanna Clarke seems to be a one hit wonder, but then again it means I don't have to sneak another book onto the island!
I will say this. If ever stranded on an island with just these five books, I would survive, partly due to them. I would also be found crying at night over everything else I had to leave behind and missed, a lot of those tears would be over Clarke, Reynolds, Gaiman, Pratchett... Oh god, the list is endless.
/me waves to a passing ship and begs a look at the library.