Erik Heels has published an interesting article about his use of Swish-E to handle his desktop search needs.
I'm using Copernic Desktop Search myself, and can recommend that. Copernic has been enhanced to include the ability to click from hit to hit through a long document, and it can index Wordperfect documents. Copernic also will index networked (LAN) drives. (Yahoo Desktop Search will not search networked drives, which is a dealbreaker for me.)