You can't swing a dead Robin without hitting an excellent DC graphic novel, but when it comes to the House Of Ideas it's a different story. Marvel characters tend to be better known for single issues (like Spider-Man's The Night Gwen Stacy Died), long runs on a title by a certain creative team (like Ed Brubaker's Captain America), or simply as ongoing series themselves.
There isn't really the same canon of classic, trade paperback-length storylines in the same vein as, say, Batman: Year One. Plus most of the more well known miniseries, crossover events or classic stories - Civil War, Infinity Gauntlet, The Dark Phoenix Saga - are so well known as to be part of the collective pop culture consciousness. You probably know what happens in them before you've even read them. They also don't really work as standalone graphic novels. Civil War would be totally impenetrable if you weren't already acquainted with the vast cast of costumed characters, Infinity Gauntlet's pretty impenetrable either way, and The Dark Phoenix Saga doesn't pack anywhere near the same emotional punch if you've not read the preceding few years of X-Men stories.
Say you're faced with the curious friend who wants to read more comics, or has never picked up a funnybook in their life. You couldn't, in good faith, expect them to jump right into Iron Man's ongoing and understand what's going on. You also don't want to just point them to a collected edition of one of Marvel's long-running series - that's way too big a commitment for a novice fanboy.
Luckily, even though they're less common than with DC's smartly packaged collections of miniseries and story arcs that work as complete stories, Marvel do have a handful of easy-to-read stories that are as entertaining, enriching and understandable to veteran comic readers as newbies.
You just have to know where to look. And it just so happens you're looking in the right place, since these are our pick of the ten Marvel graphic novels you must read before you die.