[Azizal]

Snow Crash, by Neal Stephenson is a great sci-fi book that hasn't been mentioned. It fits in the cyberpunk genre (sorta) and is also funny (main character is named Hiro Protagonist).

There is also a surprising lack of Heinlein recommendations. The Moon is a Harsh Mistress is my fave of his, tho I have not read them all.

When I was very young I read a bunch of Star Wars novels. Nearly all were crap, kinda like (I imagine many of you have done this/tried to do this) when you go back and try to read Dragonlance again. But the Timothy Zahn Star Wars series is really good.

A Wizard of Earthsea (and sequels) by Le Guin are very good too.

I ditto the recommendations of: Speaker for the Dead (hated the ending of Xenocide so much I didn't read Children of the Mind tho. Also I think Ender's Game is way overrated), Amber, Hyperion, Foundation, early Shannara books, Dune, Rama, Illuminatus (sooo good).

But my favorite is George RR Martin and it's not even close. Anyone reading this thread who hasn't read this series should make it a priority. It's so good that many times when I have been in the mood to read fantasy, I look for something new and wind up re-reading Martin instead.