Anywho, getting vaguely back on topic...
I booked a trip to Paris this fall on a whim for the DLP Half Marathon (yes, I know runDisney is one of
@WDW1974 's favorite targets, but DLP has the best course, even if their registration process is a mess) because I stumbled upon cheap flights. Roundtrip airfare to Paris from the DC area was only about $50 more than what I typically consider an acceptable price to southern California, where I go several times a year to visit friends and family.
Add to that the costs of race registration, park tickets, and hotel (off site) are all less than half the price their equivalents in Anaheim or Orlando, and it's actually a fairly affordable trip. Even when considering non-park options like museums and tours, you would be hard pressed to find things that approach the cost-per-day of Disney parks in the US, even with multi-day tickets
As others have said, I would never recommend an international trip just to visit the parks, especially for your first international trip, but they can be a great excuse to get out of your comfort zone a little. Even with several trips to Paris under my belt, it still feels extravagant going for such a quick trip, but we will still manage to squeeze in some sightseeing in the city, along with a bonus stopover day in Iceland en route
The world is an amazing place. It would be a shame to spend your vacations at WDW, when so much more is within reach for the same (or less) cost & time.