[QUOTE=Chronos]
Eh, call me when they come out with the complete set of Asimov :D.
But seriously, I don’t see the appeal of collections like this, especially not for a writer like Heinlein. Heinlein wrote some of the best books I’ve ever read, but he also wrote some of the worst. Putting together a collection piecemeal, like I and others have, one can simply buy the good ones, and pass by the bad ones, but in a complete collection, you have to pay good money for some real stinkers.
Plus, there’s a certain joy in finding a battered, well-read old copy of a book you don’t yet have in your collection at a Friends of the Library fundraiser or a garage sale. Buying the fancy, leather-bound complete set would, I think, greatly diminish that joy.
[/QUOTE]
Maybe I can explain the want and need to own all of something. First, I’ll ignore the blasphemy you have spoken about Heinlein. 
If I love an author, I will read everything they write. Even the stinky stuff. And I’ll read it more than once. Because I like the author and there is usually something I can get out of even his crappy work.
If I don’t like the author, I won’t read their stuff even if it’s a classic and must be read. I can’t tell you the number of great books I won’t read because of writing style.
I love Heinlein and I disagree that most of his books are the same one re-written. Maybe he deals with the same themes, but the books…I love his stories. Job: A Comedy of Justice is one of my favorites.
I love Stephen King too, and many of his stories really are the same. Doesn’t stop me from owning almost all of his work, including the much maligned The Tommyknockers. And I re-read this crap. I just love to collect what I love.
I do enjoy building my collections in a meandering, used book store way. But I understand the desire to own it all, in a purdy package, too.