For me, it's all about Mega Man. Really, my videogame collection started as just a Mega Man collection. Ironically enough, the one glaring hole in my collection is that I don't own any NES Mega Man games (since I don't own, and never did own, an NES) though I intend to one day change that. But apart from videogames, I own about 6 Mega Man mangas (english release only. Not hardcore enough for other languages I guess), the 4 Archie Mega Man comics released thusfar (though I may go back and get multiple copies with the alternate covers), a couple models, a toy or two (or six or seven), a custom Mega Man X T-Shirt my girlfriend made me, a few official OSTs, two art books (Mega Man X and Mega Man Zero, slowly acquiring the rest), and an 8-bit Mega Man plush doll that my girlfriend also made for me. There may be more, but that's all that I can think of at the moment. One day I'll take a picture of my collection thusfar.
So in short, I'm obsessed with Mega Man and I have an awesome artsy-fartsy girlfriend.