You can change what the Power Button does when you press it. Make it Shut down, Hibernate, Sleep or Do Nothing via Control panel.

You'll see an icon in your taskbar from which you can toggle power plans with a single click, as well as change the brightness by right clicking.

The Windows 7 taskbar combines window management with an application launcher, since you can right-click on any item and pin it to the taskbar, but that's not nearly enough for a power user.