I only collect a few comic books: Ps238, Astro City, Lone Wolf and Cub, and Usagi Yojimbo. Except for PS238, which has not yet released such a compilation, I wait for the comics to come out as a book-bound "graphic novel".
The first is just cute. It's about an elementary school for kids with super powers. It is the reason I go to the local comic book shop a few times per year.
The second is, in almost every issue, a literary masterpiece. It begins with a series of adventures of comic books characters that are quite similar to familiar ones, but ten times as interesting and human. Then it did a long story arc that was the most interesting exploration of faith I have ever seen in a comic book. Recently it was exploring how living in a place with superheroes would affect the lives of normal people. Sadly, it seems to have stopped being written sometime during the last year.
The third is a classic about a child growing up in a world of violence, corruption, and lechery -- living in that world but not being of it. There are a lot of striking parallels between his dedication to bushi and a believer's dedication to Yeshua. I find reading the issues I own is not only entertaining but a reminder to not become soft, or compromise my dedication to a life dedicated to God. I certainly would not recommend this last comic to kids, and I find books 19-26 too repulsive to enjoy (these focus on a really unpleasant villain, an expert in poison who is vile in many ways). It is a completed series, but I do not yet own all of 1-18 and 27-28.
The last explores the same themes of honor and purity within the corruption and violence of Edo-period Japan. But it's written for kids. Rather than being one long story, Stan Sakai is retelling classic Japanese myths and legends using animals. His characters are wonderful, and what make the comic worth owning. In some way's it is a Lone Wolf and Cub for children, but that is not really describing it well.
Anyway, I recently saw two places on LiveJournal designed for people to share scanned copies from their favorite out-of-print comics. For example, here are unusually interesting stories about Doctor Octopus and the Hulk. Clearly most of these site's readers would buy copies if they were available: this is the collector fan-community "geeking out" together. I wonder if the comic book artits and publishers are upset at the copyright infringement or not? Perhaps they must avoid encouraging this but are quitely appreciating knowing which old comics to both reprinting without losing significant business?