depends.
what kind of books do you like? have you read a bunch previously?
for fiction:
the most epic book i've ever read (full-on fantasy land, at least as good as LOTR) was "memory, sorrow and thorn". fucking epic.
"shogun": a tale of white man's first contact with the japanese. has war, sex, and culture shock. pretty damn good book.
some easier reads:
Where eagles dare: classic james bond-esque book.
malcom gladwell (an author) has been mentioned 3-4 times already in this thread, i'd like to re-endorse. his books are all about sociology/physcology, but written in a really interesting and fun way. every single book of his is a good choice, though i thought "blink" was the best. non-fiction.
for a lower reading level (i have no idea your age or reading level, no offense)
if you're new-ish to books, try the redwall series. dont go too hard to fast. you'll just kill yourself and hate reading. these books are enjoyable for any reading level.
good luck breh.