haha of course they're different! basically they're layed out by manufacturer, and then there's an easter section, halloween section, christmas section, and a random foreign brand section....the american market is a piece of cake since i live in illinois and go to school in massachusetts....stuff from the UK i pick up from ebay, import stores, internet stores, and then i picked up 60-some bars last time I was in London...elsewhere I do the same: online, mostly, and then when I travel (i.e. Spain, France, Australia, Canada), when my friends/family travel (i.e. Denmark, Korea).
It's become QUITE the obsession. I store all of the wrappers in a binder with the magnetic/adhesive-type pages used for scrapbooking and things of that sort. Eventually when I have a house of my own (i'm 18) I hope to get custom made frames to hang them in.
I actually only started about a year and a half ago so procuring the older wrappers has been a test. I've had the best luck with Ebay in terms of that.
~Jeff