With a break point set, after the DataTable or DataSet is populated, you can see a magnifying glass if you hover over the variable. If you click on it, it will bring up the DataTable Visualizer, which you can read about here.
In this image you see below, dt is my DataTable variable and the breakpoint was hit a few lines below allowing me to hover over this value. Using Visual Studio 2008.
DataTable Visualizer (image credit):
