Quicksilver is a "launcher", but it does much more than launch applications. It figures out everything about your computer, then hooks everything together so you can perform actions in an intuitive manner. It knows your files, your songs, your address book. You can find a file, say mail it, find the recipient, and done. No Finder, no dragging, no Open dialog.
I've had it for one day, so I'm no expert. Here's 3 links.
It's free. It's in beta, so you'll might hit a bug, although I haven't. It will also tell you to update every once in a while, which you should do.
It also offers a simple way to run multiple sessions of Archicad.