ESP is one of the fastest desktop search tools you'll find on the Internet. It is also quite simple to use: you type, it searches. You don't even need to click on any button, results just appear in real time as you enter your keywords.
You can also specify the folders where you want to search your files and filter your search by means of different criteria. Once you find what you were looking for, just click on the file to open it. There's also the possibility to print it, email it and a dozen more functions.