AutoCAD 2011 comes with a new useful and helpful feature.
Easily select overlapping objects using the new selection cycling functionality. You can enable selection cycling from a control on the Status bar (right click to access the Selection Cycling options). When you try to select an object that overlaps other objects, AutoCAD displays a list of all the overlapping objects. This works for both 2D and 3D. As you pass the cursor over an object in the list, the relevant object in the drawing highlights, click on any object in the list and it gets selected. You can also click on the same location multiple times and the objects with be selected one at a time. To filter the type of subobjects displayed (vertices, edges, or faces) use the SUBOBJSELECTIONMODE system variable. You can also set this option with the SELECTIONCYCLING system variable.
Wish for AutoCAD 2012: Selection cycling should benefit from also be able to show layer of objects. Imagine if you have two identical objects and only the layer is different.
Another thing that might be helpful is to be able to use the up and down arrows on the keyboard to activate the Selection dialog. Now you have to either stay still and click multiple times or to move the mouse to the Selection dialog box.