Houston. Why? Well, because they are in the lottery because of Steve Francis being injured. Having him healthy will help immensly. Add in a C like Yao Ming, and a SF like Nachbar, Houston is playoff bound.....not bad for a team that was one of the worst in the L.
But if you just want the team that will improve JUST thru the draft, Id have to go with Chicago, assuming they get Jay Williams. Hes is NBA ready and will provide some much needed scoring.