Copernic has made the 2.0 beta version of Copernic Desktop Search available.
I was extremely pleased with their previous version, and this 2.0 looks very promising. They finally added the option to search all file types, which was a bit of a drawback before. The interface is revamped, and looks a lot slicker. They even suggest search queries (much like Google's Suggest) !
I absolutely love this FREE piece of software. Can't do without at work, because you can define your own file types (like *.cs or *.js) to find that line of code you know you've once written, but can't remember for which project.
Copernic Desktop Search 2.0 Beta [ copernic.com ]