Couple of points about Everything: Almost all desktop search software works by creating massive indexes which are then utilized to quickly locate a particular file/folder/content for you. Everything does not do this, Everything leverages off the indexing which is already part of the NTFS file system. Everything still creates indexes but they are are tiny compared to other file search programs.
While this system proves to be very fast and effective, it also involves two minor drawbacks; Everything only works with NTFS formatted drives - no great biggee because the vast majority of drives these days would be NTFS anway. Also, Everything cannot search file contents, only file and/or folder names.
If speed is the primary requirement, Everything is the one. Anyone looking for something full featured with more options should check out Copernic Desktop Search Home.
BTW Guys: The native desktop search tool in Windows 7 is the best of the whole lot, but of course you need Windows 7 installed to use it.