Well, I live in the "world" part of this planet, so that's easy.
I started collecting Dutch coins when I was a little kid, saving 1 cent coins, aiming to get a full year run. Once that was almost completed, I added 5 cent coins to that and later also 10 cent coins.
Then my collecting hobby went into hybernation, until many years later I went on vacation to a diferent country than usual and took some coins with me as kind of souvenirs. That woke the collecting virus again. I decided to collect, next to the collection of Dutch coins, all coins (denominations/ varieties) of countries I've visited.
If price was not an issue, I'd really like a UNC or Proof Gothic Florin.....