I'm trying to stick to digital comics as much as possible.
Of the stuff you've recommended, from DC I've found Batman: The Long Halloween, All Star Superman, Green Arrow Long Bow Hunters and Kevin Smith's run, Green Lanter Rebirth and 1-66 of Johns' run, 1-25 of Johns' Hawkman. As for Marvel, they have Amazing Fantasy #15 and all of Lee's run, Ultimate Spider-Man 1-133 and Ultimate Comics Spider-Man 1-12, 215-294 of Byrne's Fantastic Four, 337-382 of Simonson's Thor and 1-8, most of Jurgen's Thor (there are a couple gaps I noticed), 57-74 of John's Avengers and most of 1-56 of Busiek's, and all of Morrison's New X-Men. So it looks like I've got quite a bit of stuff to look forward to. Thanks!