Need your advice about information retrieval system.

Please, I need your advice. I have vital issue of searching information on computer and in local network. I tried several programs - some do not provide satisfy search results, some are not handy to use, and some are too slow. Did anyone were interested in that kind of problem and can you advise something? Please, support your suggestions with facts.

the most recommended programs are:
-google desktop search
-copernic desktop search
-searchinform

please, help me to choose

I want to find information through the dozens of document files on my hard drive and local network… I’m trying to find the fastest and the most functional program.
Google Desktop Search can index and search documents in text formats, as well as mail, audio and video files tags and images. To be remembered: in order to show the application which files and folders to index, you have to install an additional component gdetweak. Without this add-in Google Desktop Search will index the whole information on user computer and in the network of the enterprise that it can access. Google Desktop Search by right features the most user friendly interface. But the only way to fine tune the application is to install additional components. This is a major disadvantage. The promised search of documents with a similar content (in the Internet originally positioned as similar pages) is quite wretched.

Copernic Desktop Search - is not bad. It can index and search documents in text formats, as well as mail, audio and video files tags and images. Copernic Desktop Search by right features the most user friendly interface. But this tool is too slow and index is too big. It can't search through *.chm files, for example. And there is no LAN support.