I've got a cranking rod that I love. It's just a (fairly) cheap Diawa rod and baitcasting reel combo, but it does the trick. I've usually got 12 lb. line on that, so I'll be switching that over to fluoro next year. I've got an extra Shimano spinning reel right now, so I'm buying a St. Croix ML right for that. I'll probably put 8 lb. fluoro on that setup next season.
Much of the info that has been posted is accurate, but there are many variables involved as many people have suggested. There are many good websites not necessary from manufactures that are available. Another variable in the equation is water temperature-the activity level...an example is early spring (sometimes very cold water), vs. late august (very warm water).
I am in no way endorsing any particular brand, or television show, but on Verses there is a Bill Dance fishing show, called something like "Connection", that gives much good information, one of his sponsors is a fishing line manufacture, but his 30 minutes is not necessary a commercial for that particular brand, but he gives accurate and easy to understand information. I
I love using a round braided line (such as power pro), (it casts effortlessly), but doing that you need to know how to tie a blood knot, to use the different types of lines as your leaders. Catgut-or monofillment I prefer to use with presentations of top water baits, where as floro-carbon is quite nice for throwing into high abrasion areas, where visibility (or more accurtly invisibility) is a factor. Monofiliment still might be the best all around line going, but most fisherman have several rod/ reel combo's.
A disadvantage of braided line is the cost, it is quite pricey, if you tangle it up, you need to cut it, there is no untangling it, and in high wind situations, it may not be the best choice. Floro-carbon is very nice, but 100% floro is much better, as apposed to floro-carbon coated line, when it gets older, i feel that the coated stuff the strength is jeopardized. Also 100% floro is a bit pricey also.
From my experience, purchasing line that is on sale or from a kmart might be the biggest mistake you can make. If it is discounted, whether it is from a specialty store, or a kmart, the line has probably been on the shelf a while. I have purchased line that has been on sale and had it break MANY times, in conditions where it certainly should not have. Purchasing line from a store that sells alot of line almost guarantees that you will get a fresh product. Losing a nice fish because of equipment failure is no good.
There is much to be learned on this subject is basically what I am saying, however if you stick to one line for all situations you are limiting yourself.