I've been pretty happy with Google Desktop - pretty speedy results, and doesn't seem detrimental to "normal" performance.
But I've noticed that a recent update has taken away its ability to index an external drive (NOT Flash, a regular drive). I've totally uninstalled and reinstalled, I've added the drive, removed the drive, added the drive, rinsed, repeated.
I receive a "Unknown error accessing files during crawling" at best, when I get ANY type of response on the Preferences page.
I can't find a solution, so I'm thinking time to find an alternative. Also, I'm not digging that on Windows 7, to run GD effectively, I need to turn off Windows indexing, which screws up my Outlook search (which is superior to GD, but only when searching Outlook).