Just another tip/suggestion for traveling with kids. I have found it worthwhile both from a cost and convienence standpoint to try to find hotel/villa rentals that include a small kitchen. That way you can store drinks and snacks for the kids or even prepare an occasional lunch or dinner (which can save some $).
I've noticed villa rental properties on LuxuryLink for Costa Rica, Provence, Bali and the Caribbean.
I stayed at Royal Parc Evian (mentioned in the first post) just a few months ago and can highly recommend it. We were with our two sons (aged approx. 2.5 and just under 1 at the time). There are two hotels on the site and a kids' club, and the latter is excellent for children. It has an outdoor park, lots of indoor play space, an area for them to do crafty things, a Dreamcast (I think it was) game console, a childrens indoor pool, and so on. For older ones, there's tennis, pitch and putt golf, and more... all on site. Thoroughly recommend - if you wish to read more, you'll find details about our visit here.
Another place I would recommend with respect to children is the Park Hotel Delta in Ascona in the Ticino region of Switzerland. We were there last May/June time with our two sons and took advantage of the family package they were offering at the time. In addition to the usual facilities, there is a creche that's suitable for children aged 2 and above. There's also a small outdoor pool, table football, crazy golf, table tennis, a slide and swing, a petting "zoo" (really just a handful of animals), plus ample grounds to play around in. If you'd like to know more, details are here on my blog.