Super sets are 2 different exercise sets performed one right after the other (no rest in between). I would assume giant sets are sets with many repetitions, although I've not personally heard of that term.
Super sets are a great way to stimulate muscle growth when performed properly. I incoporate these every once in a while...especially when I work on 2 "opposite" muscle groups that day. For example, on arm day, you can superset bicep curls with tricep extensions. You'll definitely feel the burn after 4-5 sets.
-------------- **_Robert_** Pain is temporary; glory is forever!