DataGridView Selected Cell Default Color

The color that I was looking for was: SystemColors.Highlight.

If you go to the Properties section of your DataGridView object. There is a property called DefaultCellStyle and under that there is a section called Appearance where the SelectionBackColor property resides. The default for SelectionBackColor is Highlight which is under System.Drawing.SystemColors.

One property to try is DataGridView.RowsDefaultCellStyle.SelectionBackColor, although you may be more interested in DataGridViewCell.InheritedStyle.SelectionBackColor.