Just spotted the line about "har dsci-fi" - you could try John Scalzi - start with "Old Man's War" he is sort of like Heinlein without the morality lectures and very funny and poignant in parts too. Or Joe Haldeman's "Forever War" - there are sequels to that but it was originally intended to stand alone, and does so very well.
Jack L. Chalker's "Rings of the Master" is a quartet, but definitely qualifies as epic.
How about John Wyndham and John Christopher? I know they aren't modern as such, but their stories were well before their times and have easily stood the test of time

After reading through what you've all recommended, there are some good reads in here. However, you've omitted Lois McMaster Bujold whose books are just brilliant. Start with The Curse of Chalion, Paladin of Souls, and The Hallowed Hunt, and work your way to other novels.

Most of them are really nice suggestions!Thanx all.