I was actually considering making this thread a few days ago. You're absolutely right about the Japan thing. Every time I look up an album on Wikipedia it seems like there are always 1 or 2 Japanese bonus tracks. I remember talking with someone on another message board about this, and apparently there is some sort of law that requires albums imported into Japan to have bonus tracks. I forgot specifically what the law states, but it's certainly no coincidence. I wish I could remember the site he linked me, because it explained everything.
Edit: Well, Bosky explained it. There you go.
To be honest though, it really doesn't bother me at all. I never listen to bonus tracks on albums unless they are studio-quality original songs. For example, I've owned Opeth's Orchid, Morningrise, and My Arms Your Hearse reissues for years now, and I've never listened to their bonus tracks. I just don't really care. The standard album tracklisting is usually enough for me.