what's a really good sci-fi book?

Hmmm...I'm not too into sci fi so these are fairly well known and probably books you've read but they are some favorites: Hitchhikers Guide to the Galaxy - Douglas Adams - I've only read the first book so far but I've been meaning to get to the others. Its hilarious and creates a great universe. Do Androids Dream of Electric Sheep?, A Scanner Darkly and pretty much anything by Phillip K D*ck. I think Do Androids Dream of Electric Sheep is about much more than a guy hunting androids, but its still enjoyable on that level. Snow Crash - Neal Stephenson - there is a lot of interesting philosophical stuff thrown in and the ending is a bit lame but its a book I'd recommend to Sci-fi fans. Prob a bit more cyberpunk. I could prob come up with more but I'm drawing a blank