" Tekken 5 is in my view the pinnacle of the series. "
You have good taste mate.
Indeed. I'll also add Tekken 5 doesn't have the worst move in Tekken history. Asuka's counter throws (back plus throw). It can be performed so quickly and without precision (unlike other character's counters which rely on a punch being thrown at the exact moment you use it) and can counter someone before they know what has happened. A joke of a move.
Oh, on subject, I'll add Bloody Roar 2 and Tobal No 1 for memory sake.