Spain with 11 & 9 year olds

[Ineedcaffeine]

having been rained off our camp site in Cornwall (again) :-( , DH has decided that next year we're going to Spain!
As this will cost far, far more than our normal camping trip, before we go ahead and book I'd like some advice, please from anyone who's taken their children to Spain.

• Board basis - self catering is cheaper, but does it work out more expensive in the long run? My kids aren't too pernickety when it comes to food - one would happily eat chicken nuggets every day, whilst the other loves pasta - so I'm not sure what board basis to opt for. I suppose it depends on the quality and variety of the food offered. I've heard awful reports of giant queues for All Inclusive, and feel that might be too restrictive.
• Entertainment - would like some (as ED is now at the age where she's fascinated by all things singing and dancing - no matter how bad!!); but not all through the night - as even on holiday, I'm not keen on keeping the kids up too late. *Pools - flumes vs no flumes?

Any information about what I need to know/avoid so that we all have a good time would be muchly appreciated, thank you.

I be taken the girls to Mallorca many times, last time at 12and 9.
We've done half board most times. The buffet breakfasts are huge fun and by 9 the evening food should be fine. Everywhere we've gone does some kids stuff.
Evening buffets are great since DD2 has been known to fall a sleep waiting for meals in restaurants and then eat nothing.
You can buy child friendly lunch every where and not be tied to the hotel (interesting adult food is harder to find).
also you can buy ham, olives cheese etc and picnic on your balcony, cheap and great if hot children want to unwind. Ask your rep for the nearest supermarket, prices of water, soft drinks etc are ridiculously better for a few minutes walk away from the hotel in someplaces.
Eroski's is your friend if you are in some bits of Mallorca, basically Tesco's
My only other advice find the biggest nicest pool you can and the shortest walk to the beach.

Flumes are great, never had on at the hotel, but DDs and parents like water parks.
Yes hotels have queues for food, but they come and go at certain time, sending some one down to spy can work wonders.