Yes, it's my birthday! And thanks in advance for any expensive presents you may want to lavish upon me. Actually, your joy in solving this puzzle and finding the cache is all the gift I will need!
To solve the puzzle, you only need to figure out my age, at the time of this posting, and one other piece of information. Take a look at this picture montage. The things represented should point you to something (we'll just call it "the item", to avoid giving too much away) that will tell you my age. The item was created by a very famous person, when he was just a teenager. Just multiply my age by his age at the time the item was created, divide the result by 1000, and add to both the north and west components of the posted coords.
(Sorry, no checker. Don't want to encourage any trial-and-error solving.)
Congrats to SGF for FTF!