My Spotlight indexer process was consistently using 75-150% CPU. Since I *never* use Spotlight for document content searches, and *only* use it for app launching (really, Alfred (http://alfredapp.com) on top of Spotlight), I added ALL hard drive directories except for my Applications directory to Spotlight’s Privacy tab (System Preferences > Spotlight > Privacy).
The Spotlight indexer process is now silent, and my battery life has doubled.
