Here's a few series that I've really enjoyed: - The Culture series, by Iain Banks. Great space opera series with plenty of dark humor and moral dilemmas. - The NASA trilogy, by Stephen Baxter. Three separate books (no interconnecting storylines), each exploring different fictional NASA missions and the ramifications thereof. Moonseed is probably my favorite of the three, but the others are all amazing. -Discworld, by Terry Pratchett, especially the City Watch sub-series. Great characters, humor, and storylines all mixed in an amazing fantasy setting. -The Saga of Seven Suns, by Kevin Anderson. Another space opera, with politics, space battles, genocidal alien races, and all that. -Pretty much anything by Brandon Sanderson. His Cosmere books are amazing fantasy writing and every one of them is great. Also a bit of state pride there, since he's from Utah and so am I.