I really like Park Hyatt. The JW Marquis is (I believe) the worlds tallest hotel. Each one is on a different side of the creek (Hyatt 'old', Marquis 'new'). The Hyatt is a reasonable distance from the sites but it is a cab ride away, the Marquis is pretty much among the new architecture builds. As for sites it's hard to recommend what to see but the obvious ones are Burj Khalifa, the worlds tallest building, the Aquarium in the Dubai Mall, free to see, absolutely massive. Also are you flying in/out of DXB or DWC? That will affect things.