Hi - there's a couple of authors/books I'd recommend:
Peter F. Hamilton - writes big 'space opera' novels and sagas. Try 'The Reality Dysfunction' - I think it's a fantastic book, but beware it's about 1000 pages, and the first in a trilogy (so together the three books weigh in at about 3000 pages). If you want to try something a little shorter first, he's also written a stand-alone sci-fi/space opera novel: 'Fallen Dragon'.
Iain M Banks - His 'Culture' novels are good and very popular, though some I found difficult to get into. His first one is 'Consider Phelebas', and my personal favourite is 'The Player of Games'. Haven't read them all, but as far as I know they're all stand alone novels, though loosely connected to each other.
Lois McMaster Bujold - She's written quite a few science fiction novels about a character called Miles Vorkosigan. Think they're all between 300 and 500 pages each and are stand-alone despite being linked. It's best to start with the first one if you can - it introduces the character and sets the scene for future books. The first Miles Vorkosigan novel is 'The Warriors Apprentice'.
Stephen Baxter - Quite a prolific and popular UK science fiction author, I'd highly recommend his Xeelee sequence of novels. First one is 'Raft', and then there's Flux, Timelike Infinity, Ring and Vacuum Diagrams. His novels are part space opera, part 'hard-sf'. But the technical science aspects don't interfere with the story, and they're easy to read for the non-science types (like me). He's written other, different types of SF novel, some of which I've read, but wasn't as keen as I was on the above books.
Here's a couple of older SF novels set in space that you may like if you've not read before:
The Forever War by Joe Haldeman (only about 300 pages and an exceptional book in my opinion).
Ringworld by Larry Niven
Hyperion by Dan Simmons.
There's probably more, but that's all I can think of for now. If I think of more later I'll add them.
Hope this is useful.
Nakmeister