I just noticed today that Launchy has had a fairly major upgrade and is now at version 1.0.
The new version adds support for plugins, and some of the new plugins add the ability to browse and open folders, and to browse and open FireFox bookmarks (not sure if IE is supported), and the ability to search some popular internet sites (google, wikipedia, etc) directly from Launchy.
Launchy has still got a ways to go before it’s as good as QuickSilver is on the Mac, but the Launchy team seems to be making some decent progress. IMHO it’s probably the best QuickSilver substitute for people on Windows.
