I might have missed something, but I am suprised that Light Gun games have gotten no love! I never really did like House of the Dead or House of the Dead II (because I died an awful lot) but Time Crisis II and Crisis Zone have got to be the arcade games that I have spent the most money on. I am not sure of its predecessors but the Time Crisis series was (probably) the first to use the pedal system, and while on paper that may not seem like some revolutionary enhancement, it made the game a great deal more fun because you don't die everytime you are to slow to move the gun. And the co-op mode in Time Crisis II was pretty awesome as well; having two players on different screens experiencing the same action but from different angles was way cool.
Light Gun games rule!
The pen is mightier then the sword, and considerably easier to write with.