FJ, you could always send the "I don't care" back in his direction. Except it works much better if you say "I don't mind". Eg "I want to catch the bus Mum". YOU: "Hmm, I don't mind that you want to catch the bus, we're going in the car". You simultaneously acknowledge what he is saying BUT let it roll off you completely. Trust me this strategy is a winner for overcoming complaining!!

Ok, so the charts don't work because you haven't worked out what the bottom line is for your kids. Pocket money, sweet foods, time on tv/computer games, time with parents at end of day, confiscating favorite things (ie bike/trampoline/mp3 player goes away for hour/day/week), even family events like trips to the park, are all things you can use or remove for leverage. There's always something that works.