Here's an interesting way of depicting the statements that are likely to have cause test failures:
http://www.cc.gatech.edu/aristotle/Tools/tarantula/ Tarantula displays each source code statement using color models that reflect its relative success rate of its execution by the test suite. Roughly, statements that are executed by a failed test case become more red, and statements that are executed by a passed test case become more green. - Barrie