Disneyland Paris seems to always have things in refurbishment so it's really hard to plan a trip there without at least one thing being down. My last visit had Space Mountain and the Nautilus both closed for refurb...and if I do in fact head there this summer, it'll be Phantom Manor that's closed during that time.
Disneyland used to be like this too but it seems they've calmed down a little bit on the refurbs (although if you were to visit right now, you're down Haunted, Splash, Dumbo, Screamin, Grizzly..)..