Kurina: This is pretty much how I am as well. I am not one to hold onto objects for any length of time, but video games seem to be the exception. I take a bit of joy in seeing them lined up along the shelf, remembering the fun times I have had with many of them. Even if I do not play them regularly, just seeing them can still bring a smile at times. Additionally, as you mentioned, it is fun to look back at all the packaging and contents, seeing the creative effort put behind a lot of the materials.
I am only saddened by the fact that as a kid, I did not have the foresight to hold onto some of the games and materials that came with old DOS games. The manuals the size of textbooks, crazy extras, etc. I miss that stuff.
Video games are the only things I collect too... well, Doctor Who DVDs I guess, but that's mostly because they're sold in a way that makes you collect them. I can't imagine collecting EVERYTHING I am interested in and buy... that would be insane.
And I'm with you on the old stuff... I sold ALL my games in 2003 I think it was, because I was "out of gaming." That lasted like a year or so and now I have to buy them all back, including the hard to find old ones.