QuickSearcher

QuickSearcher is a file search tool. Decided superiority is Preview for text search (as well as preview for graphical files), ability to search within several folders (multi directory search) or within search results, setting favorite search folders and off course, ability to save that search results. 
Another useful feature is searching within some archive files (ZIP for example) and searching for MS Office documents and MP3 (you just should specify artist or composition name). And finally QuickSearcher have a handy system integration and beautiful interface.