Quicksilver

Quicksilver is a great little app that gives you control over a LOT of features in your computer just by typing anything you want. For instance you can use Quicksilver as a launcher, where you would just type "iTunes" and hit enter and iTunes opens. But say iTunes is already open, then you're given a new set of options if you hit tab instead of enter. You can look through playlists, change the volume, or add the current song to a new playlist. The other great use for Quicksilver is using it as a spotlight that can also control your media and search through bookmarks and web history. Look below, I started typing clutter because I wanted a file inside that folder and this is what came up:

Next we have a screen shot of an add-on to Quicksilver called Constellation Menu, it lets you see things much more graphically for certain applications, such as iTunes, seen below.

Quicksilver has a plug-in for just about any application you use, and the repository works much like a Linux distribution system. You just go into the preferences and check off which plugins you want to be installed and they automatically download and install, no hassles. Hopefully Apple will take notice and add some of this functionality right into spotlight when Leopard arrives... or maybe later on. They do need to have things to upgrade too, they can't start with everything.