there are 4 disney theme parks in the world,
The orginal DisneyLand in Anaheim, California (near LA)
DisneyWorld in Orlando, Florida
Tokyo Disneyland in Chiba (near tokyo)
Euro-disneyland in France, near Paris
They're building another in HK
I've been to 3 of them, except Eurodisney. (I was in paris but did
not go to eurodisney)
Disneyland is great if you've got abt 1-2 days to spare and you are
visiting the west coast of the US. some great rides are space
mountain, indiana jones adventures, pirates of the caribean,
etc.
Disneyworld is actually a theme country. It has 4 theme parks, (the
magic kingdom, epcot, disney/mgm studios, animal kingdom), 3 water
parks, a shopping area, and many resort hotels. You need abt a week
to see everything. It has it's own transport system, fire station
and ambulances, etc. I had a wonderful experience there. If you
have the chance, try to stay in the resort hotels there. Not only
do you get to go to the theme parks before they open, you'll also
get to enjoy the atmosphere there.
Tokyo disneyland has a new addition, disneysea, with water theme
rides. the bad thing is that most of the narration, ride
explainations, etc are in japanese. Unless you know japanese, this
is going to lower your enjoyment of the rides.
I've never been to euro disneyland, but I've heard that it's the
poorest of all the parks. Every thing is in french, and the cast
members ( what disney call's their staff) are not very frendly.
Besides when you are in france, there are better things to do than
go to a theme park, right ?
I would highly recommend that you try to go to 1 of the theme parks
if you have the chance. It makes you feel very young and happy,
like all your childhood coming back 
Other interesting and excellent theme parks : sea world, universal
studios, and the less interesting ones : WB movie world in gold
coast
If you have any questions, feel free to ask me. I'm a theme park
junkie 
