Thanks so much for the advice. I think we will follow your advice exactly! A few more quick questions if you don't mind...

1) How much do you expect we'd pay to hire a cab for 3-4 hours?
2) Will our luggage be safe if we leave it in the taxi while we walk around the sites or would it be considered rude to take it out each time we leave the taxi?
3) How much would it be from an airport hotel to Madinat Jumeirah?

Thanks again!!!