In addition to the Select By Rectangle tool, four new tools have been added at ArcGIS 10 for working with selections. You can now select by polygon, lasso, circle, and line. When using the Select By Line and Select By Polygon tools, you must double-click or use the ENTER key to apply the selection. For the Select By Lasso and Select By Circle tools, you click and drag the tool to define the size of the selection extent.
In ArcGIS 10, the selection tools also respect the snapping environment. This can be particularly helpful when using the Select By Circle tool to create a selection at a specified distance around a point. To specify a selection distance, click and drag out a circle and press the R key to bring up the radius dialog box. Enter a radius value and press the ENTER key.