i use 3-6 foot 10-20# flouro leaders w/power pro, but i'm kinda anal about fish seeing anything but the lure. if you're just starting out (pp can be tough on fishing beginners, but if you've got experience it's a pretty painless transition), or baitfishing, no need to use anything but a good mono in the vast majority of situations. there are countless threads regarding power pro if you do a search on it, those should answer any questions, though i'd love to extoll its virtues (sensitivity, strength, casting distance) here if you need help
see above about spooling with flouro. expensive, stiff, tough to cast, memory like an elephant. for leaders only.