Some helper apps I find useful in my Mac OS X menu bar: Synergy (registered) to control iTunes, Quicksilver (freeware) to load files fast, WeatherPop (freeware) for current local weather, Deja Vu (registered) for automated backups, Desktop Manager (freeware) for multiple workspaces, Menu Calendar (freeware), iScrobbler (freeware) for music tracking.