Make a list of the top 10 to read. I have all the Sandman and have read Watchmen before.
Ten of my personal favorites in my collection, in no particular order....
1- Richard Stark's Parker by Darwyn Cooke
Gritty crime-noir that perfectly captures the aesthetic of 60's era heist/detective/gangster stories........there's nothing in my collection that is more perfectly tailored to my tastes, or that I enjoy sitting down to read with a glass of bourbon, more.
2 - Criminal by Ed Brubaker
Criminal is another gritty crime-fiction series of stories, but less inter-connected than Parker, and told through a more modern lense. Brubaker is flat out one of the best writers in comics, and his wheelhouse is this kind of crime-noir. If Quentin Tarantino wrote an original comic book series, this is what it would look like. (QT's film adaptations to comics are pretty solid in and of themselves)
3 - Saga by Brian K Vaughan
Much more fantasy based than anything else I read, but for my money it's the single best monthly comic on the market right now. The title is befitting of the series as Vaughan is building an epic, ambitious, original world that could only be the backdrop for an epic saga of a story. It's Star Wars with more geopolitics, sex, swearing, and larger thematic undertones. It's also just flat out a blast to read.
4 - Stray Bullets by David Lapham
STRAY BULLETS foils synopsis because it has no central conceit, not even a particular setting to tie all these intricately interconnected vignettes together. It unfolds from Baltimore to Los Angeles, between 1978 and 1997, but there’s no end game, no huge plot point that this thing slouches towards as it darts from future to past, from east to west, dropping in and out of continuing stories with little regard for the reader’s confusion, each issue somehow a part of this stunningly detailed universe as well as a thoroughly satisfying self-contained story. Lapham tells the parts and pieces that he finds interesting, tossing us into already-unfolding crises and letting the chips fall where they may, suddenly picking up shards and strands of stories that seemed long forgotten.
Just a great oddball existential collection of fascinating stories.
5 - The Invisibles by Grant Morrison
Trying to summarize the plot of The Invisibles is a losing proposition; Morrison claims much of the story came to him after a metaphysical experience in Kathmandu. He decided to incorporate his experience (which he sometimes likens to an alien abduction by beings outside three-dimensional space) into the story. The book, then, would become a delivery system for esoteric knowledge, a spell designed to change readers for the better. Probably the best way to think of it is as an elaborate initiation ritual.
http://www.theverge.com/2012/12/22/3793690/the-classics-grant-morrison-the-invisibles
Biggest omnibus in my collection with over 1,000 pages....and It's really goddamn out there, but it's got some similarities to the kind of vibe Sandman has....while simultaneously being a pretty unquestionable piece of source material for what ultimately became The Matrix movie. Like much of Morrison's work, it asks a lot more of it's readers than most other material and isn't something to enjoy passively.....but if one is willing to put the work in, it's a pretty rewarding & entertaining read.
6 - Preacher by Garth Ennis
Merging with a bizarre spiritual force called Genesis, Texan Preacher Jesse Custer becomes completely disillusioned with the beliefs that he had dedicated his entire life to. Now possessing the power of "the word," an ability to make people do whatever he utters, Custer begins a violent and riotous journey across the country. Joined by his gun-toting girlfriend Tulip and the hard drinking Irish vampire Cassidy, the Preacher loses faith in both man and God as he witnesses dark atrocities and improbable calamities during his exploration of America.
..about to be a AMC show, produced by Seth Rogan.
7 - From Hell by Alan Moore
Really dark sick & twisted fictional tale of the events surrounding the Jack the Ripper murders, with Moore having done a ton of research to build his narrative. One of the more unique graphic novel reading experiences I've had, as half of the story is told through comic book story telling, while the other half is told through chapter by chapter footnotes/addendums that further the story & explain what aspects were based on evidence and what elements were creative license. Not the funnest book you'll ever read, but it's unquestionably imo an all-time classic.
8 - Gotham Central by Ed Brubaker & Greg Rucka
Just a real interesting take on Gotham & the Batman mythos......basically a Gotham version of The Wire/Homicide Life on the Streets/Law & Order type police procedural, with Batman primarily a background figure as you follow a group of detectives trying to solve crimes in Gotham. Really interesting/original take on the super-hero genre.
9 - All-Star Superman by Grant Morrison
Just flat out the best Superman story every told, imo.
10 - The Fade Out by Ed Brubaker[/b]
An intricate and groundbreaking crime story on a level Brubaker and Phillips have never tackled before, THE FADE OUT weaves a tangled web through the underbelly of a 1948 Hollywood... A noir film stuck in endless reshoots. A writer plagued with nightmares from the war and a dangerous secret. An up-and-coming starlet's suspicious death. And a maniacal studio mogul and his security chief who will do anything to keep the cameras rolling before the Post-War boom days come crashing down. THE FADE OUT is the most ambitious series yet from the award-winning Noir Masters.
Other than Saga the only ones on this list that are still on-going, and Fade Out is currently only 9 issues in.....and you can pick up the first trade paperback (collecting the first 5 issues) for $9.99 at virtually any comic book shop, or on Amazon. Only book other than Saga that I buy every single month when a new issue comes out.