I'd love to see a Preacher miniseries, preferably on HBO where it can be just as nasty as the comic was. I want to see The Saint of Killers mixing it up with an armored company!
Most of the other comics I've loved have either been made into movies (some of which were pretty good, like Iron Man, Sin City and Watchmen) or are being made into movies. Others are essentially unfilmable, such as the Infinity titles.
I'm not sure about The Boys. I love Garth Ennis, but the series doesn't grab me the same way some of his other work has. It would probably make a decent movie, and I'd end up seeing it, but I'd be thinking about Herr Starr the whole time.