I've been on a couple of holidays with In The Saddle (www.inthesaddle.com), which have been fantastic. I met quite a few people who've been on a number of holidays with them and there was rarely a bad thing to say. In Spain, I can personally recommend the Los Alamos holiday - fantastic horses (all Spanish crosses), brilliant riding on sandy tracks plus great food with plenty of wine! A real home from home.
I've been told that Renegade Rides in Wyoming (also offered by In The Saddle) is really good though apparently slightly nuts and not for the faint hearted! The other ride I've done is their ride across the Wadi Rum in Jordan, which has to rank as a holiday of a lifetime.
Friends of mine went to Montana on one of those ranch holidays. Her husband was going to take his golf clubs as he didn't think it was his thing, spoke to him when they got back and he said "I've stayed in 5 * hotels all over the world, but that was the first holiday that I've ever been on, that made me cry because it was coming to an end !!"
Now I think that is a high recomendation, I know it wasn't cheap but it sounds like it was worth it !
Thank you so much everyone for your suggestions I want to surprise the OH (yes she does ride) and at the same time get the kids away from the computer screen as they only ride a little at the moment.