With the exception of one comic all of these titles come out of the eighties--the decade of John Hughes, Cindy Lauper, and Tom Selleck was ironically the most important time in comics since their birth. Forgive all the superhero titles, but it’s what I know.

Sandman
The first mainstream comic series with nary a spandex clad avenger in sight. Gaiman set a new standard in comic storytelling that hasn't yet been surpassed.

Watchmen
Moore and Gibbons show us the problematic nature of superheroes. Spandex will never seem the same.

Dark Knight Returns/ Year One
Miller redefines an icon for an entire generation.

Kingdom Come
Ross and Waid remind us about why superheroes work.

Calvin and Hobbes
Bill Waterson actually gives America a reason to turn to the funny pages again. Calvin and his imagination can barely be contained by four panels.

Maus
Spiegleman gets a pulitzer and shows the world why comics matter.

The Question
While technically a superhero comic, it was actually an exploration of the zen philosophy and the nature of identity. Great reading with some pretty nice artwork as well.

Concrete
Paul Chadwick’s work refuses to be classified. It’s about a man who had his brain transplanted in a giant alien body. It’s also about everything else you could think of.

Elektra Assassin
I just needed something with Bill Sienkewicz. A comics visionary if every there was one.

Spiderman: Fearful Symetry
My personal sense of nostalgia dictates that I have at least one Spider-man story, and this one's the best.