We've been to Europe several times; lived in Germany...at this point in my life I'm happy to go to WDW rather than back to Europe. Would go for a trip to Australia and NZ but haven't yet convinced DH.
(It's late so I haven't read through all the responses, but here's my humble two cents...)
Go to Europe. It's life changing. At least it was for me. I've now lived for several month stretches overseas and am working on making it permanent. (I keep having to come back and forth due to the visa laws.)
Disney is still going to be there.
In less than two months, I'll be heading to WDW for my European boyfriend's first ever Disney trip! I can't wait!
(I also recommend Disneyland Paris - but it's definitely not the same as WDW.)