The Remains of the Day is a short book, one that I read in a few hours, but with a lot of substance. It follows the narrator, Mr. Stevens--no first name, as he's not on a first-name basis with anyone--as he takes a trip through the English countryside and ruminates on his career as a butler. The more he talks, the clearer it becomes that he's not as satisfied with his life as he tries to convince himself he is, and that his rationalizations don't quite hold water.
For me this is pretty far toward the "literary" end of the spectrum, and I'm not generally a fan "mid-life crisis"-type books (well, this is more of a "late-in-life crisis" since Stevens is past middle age). So why did I like this one? Several reasons. It's well-written, in a completely convincing voice, and without pretension. Stevens alternates between anecdotes from the past, ruminations on his life and the simple tale of his current trip, all while sounding the way I imagine an actual English butler raised in the early 20th century would talk, without getting bogged down in heavily literary language. And there's no padding here: the book is the length it needs to be, long enough to tell the story but short enough that individual incidents are still meaningful. It's very understated, and makes the reader think, but you don't need an English degree to understand it either.
In terms of emotional involvement, I prefer Ishiguro's more recent novel, Never Let Me Go; this is a high-quality book but didn't grab me with the same ferocity. (On the other hand, I didn't have the issues with the premise here that I did with Never Let Me Go.) This novel deals with many of the same themes--most notably, with people unquestioningly handing control of their lives over to others, and losing everything that's meaningful in the process--and it does an excellent job, but often more extreme scenarios are simply more hard-hitting. Nevertheless, this book is likely to have more real-life relevance for readers, particularly if you've ever defined yourself by your work or let yourself focus on little things to the exclusion of what's really important (and come on, who hasn't done that?).
So I would recommend The Remains of the Day to anyone looking for an intelligent but accessible literary novel. It will take up very little of your time and will almost certainly be worth it.