If you're a power-user, then you like to execute tasks in the quickest way possible. One of Vista's tools that is greatly under-used is the Address bar, and it can do alot more than just search Indexed locations. It can be used as a Run dialog, Search, as well as a browser.
If you have a high-resolution display (and who doesn't nowadays), then you can make full use of this multi-purpose tool, and it can take up as much or as little desktop space as you want. Having it always available saves you from having to click on the Start button, and you can browse through your history of previous web pages, searches, and commands.