From about 2000-2006 (basically, until I got really into board and minis games) I was a serious armchair gamer and collected a pretty awesome library of RPGs I won't ever play. When you're in the right frame of mind, they are fun to read and analyze and sometimes even spur you into forming a group! I have Dogs in the Vineyard and it is an interesting read -- Rude next time I see you I'll try and remember to loan it to you. I bought several other of the former RPG.net darlings like Exalted (got really into this for a while, dreamed of running it, but it was just too complicated and I didn't think I I could talk Enron and Aeryk into playing a rules-heavy, anime-inspired kung fu game, in a million years
JR0N: Let's create characters!
ENRON: My character's name is "Fuck You" and he drinks blood.
AERYK: My character's name is, "Jonzgay Posterson"
), Tribe 8 (post-apocalyptic game about tribes of mystics fighting demons in the ruins of Canada, with a serialized plot that was supposed to be totally awesome), Orpheus (White Wolf occult/sci-fi investigation series where the twist was that some of the investigators were ghosts themselves), Scion (another White Wolf miniseries that was about people who are demigods of various pantheons in the modern day), and Nobilis (I don't even know what the fuck). Then there are the various Savage Worlds campaign settings, which I bought a lot of back in the day but pretty much stopped buying a few years back, although I couldn't resist the Space 1889 book.
A lot of this stuff I sold off on eBay last year but man I still have quite a bit of it. Especially 3e stuff. I should just throw that shit out and cut my losses.
I have 10 or so 4th ed books, but I stopped collecting them, because I just don't think it's that hot. Fights are just toooo long and I don't find the setting information inspirational. I enjoy the campaign I'm playing in, but it's more despite the system than because of it.
I do give myself carte blanche to pick up anything in the new WFRP line, because I actually do run that. With everything going on lately it's been tough for me to get a game together but I'll get it together soon. 10 advancements or bust!
I also have a couple of books for the 3rd edition of Earthdawn. This is like my dream game to run someday, but I think I'm actually scared to run it because it might ruin it. I bet Aeryk knows what I'm talking about.
I did pick up one new game lately and that is Castles & Crusades. This game is basically 1st ed AD&D with the insane stuff removed and a unified d20 mechanic. I was thinking if we ever did a man-con again or whatever that this would be a really good game to play, because I think it'd be more fun than relearning all the weird exceptions of old D&D, but would also be familiar feeling and it'd be very easy to port old adventure into. Rahasia, we'll get you yet!