Best hotels are on the beach many miles away and hugely expensive, but the Riviera Hotel on the creek, 10 mins from airport yet also right in the city centre, is great, ask for creek-view, and when I stayed there I was able to negotiate a much lower rate than advertised on their website (rivierahotel-dubai.com).
Horce races are on Thursday evenings and camel racing v early on Friday mornings! Fish and meat market beside the Hyatt is also fun.