"...people pick up the mouse to click "Go", "Search" or whatever after typing a query..."
Tell me about it! Watching people type in their Active Directory Username/passwords is a dismal experience.
Move mouse -> click in username box (it already has the cursor in it)
Move mouse -> click in password box (hit Tab - the one above capslock, fool)
Type password (watching screen after every letter to make sure they go in - it's a row of dots!)
Move mouse -> click OK (just hit return for goodness sake!!)