Dusknoir. My favourite Ghost type is, and always will be, Dusknoir. Basically, it's because of what happened long ago. When I got my first pokemon card pack, the first card I saw was a Duskull. Because of that, I've dreamed of having Dusknoir on my team for years, but I couldn't because all I had was an emulator (and I did not think it was possible to trade), and had a DS that eventually broke (sad story).
Anyway, years later after that card, I had a Dusclops that was already level 70+ after the Elite Four, saved up to get a Reaper Cloth in OR, then found someone to touchtrade with. I finally had my Dusknoir that I always wished for, which is a reason I chose OR (another reason was for the nostalgia).