After browsing, I rate the Desk Top Search in order of my preference:
(1) Xi Desk Top Search (Best but Retail only), (2) Yahoo Desk Top Search (based on Xi. Has a very wide selection of file format recognition.), (3) Google Desk Top Search (Good in some popular areas, but weak in some file formats.) (4) Microsoft Desk Top Search, (it currently does not have an Uninstaller and so not possible to remove, so I do not favour it for this reason.) Except for (1) all others are currently freeware and some in beta.