How about Port Aventura in Spain, near Barcelona ?
It is outside Salou which is only 2 hour flight time. You fly into Reus airport which is about a 15 minute coach journey to the park. We have been there the last 2 years.
It is a single complex of 3 hotels, a massive theme park, and an terrific water park.
The hotels are excellent, we stayed at the El Paso, and you get free entry every day to the theme park so great for kids. You also get free access (some days) to the water park.
Each of the hotels has a nice swimming area, and some evening facilities for the kids. The theme park and water park are very close to the hotels.
It is not tacky at all. We were happy to let our 15 year old son walk to the theme park on his own.
We spent almost the whole time in the hotel, theme park, and water park, but you can go to salou (about a15 minutes walk) if you want to.
Here is the web site:
http://www.portaventura.com/home.asp?pIdi=uk
Any travel agent will have brochues with it in.