Recently started reading again heavily after a few years off, getting right back into fantasy / sci-fi.
Ender's Game by Orson Scott Card
Dune series by Frank and Brian Herbert, obviously.
Everything by Isaac Asimov, but especially the Foundation series.
Stainless Steel Rat by Harry Harrison
Anything by Phillip K Dick and the Cyberpunk genre of the late 80's early 90's is well worth reading.