Those are not all Apps, some are system Prefs. The rest are apps that place themselves there.
That's my desktop in that picture by the way...
From left to right they are:
Yahoo Widget Engine (app), Disc Spy (app), iPod Eject Menu (app), Disc Space (app), Wrap Around (app), Main Menu (System Pref), Spaces (System Pref), Audio Hijack (app), Cee Pee You (app), Menu Meters (System Pref), iSync (app), Bluetooth (System Pref), Lock Screen (System Pref), iCal (app), eject menu (app), Airport (System Pref), Displays (System Pref), Sound (System Pref), ASM (app), International Support (System Pref), Date/Time (System Pref), Fast User Switchin (System Pref) and Spotlight (app)