Until it's built in in OmniFocus (hint) this is one way to get to your next actions fast. Assumptions are you are using quicksilver, and you are using hide, not minimize,

Quicksilver: add a trigger, in subject enter '.' to switch to free text, then this


tell application "Finder"
activate application "OmniFocus"

end tell


In the subject, select Run as applescript. Assign to your fav keyboard shortcut.