I use iTunes to DJ various events and the upgrade to 7 has removed my window display shortcuts (command 1 for main window, cammand 2 for eq) found a fix though:
In System Preferences -> Keyboard & Mouse -> Keyboard Shortcuts, I added for iTunes:
Menu Title “iTunes”
Keyboard Shortcut: ⌘1
Menu Title “Show Equalizer”
Keyboard Shortcut: ⌘2
You have to quit and relaunch iTunes for these to take effect, but they work to both show and hide the iTunes and equalizer windows.