Most valuable games you own?

[Acevil]

http://www.amazon.ca/gp/offer-listing/B002GJRQQY/ref=dp_olp_all_mbc?ie=UTF8&condition=all
Only problem is that book is a bit worn out (You literally open the book and the spine smudges)

Given I own an amazing amount of JRPGs that might be just a little bit less than that.