Man, this could develop some long long responses.
First off, line types:
Basically, I use 4 types, Cabellas Pro Line mono, P-line, Fire Line, and Mason's Braided nylon. It obviously depends on the application intended.
For spinnerbaits, buzz baits, and some other relatively fast moving baits where feel and stretch is an issue, I like P-Line better than mono or spectra type braid. P-Line is a polymer type line like mono and has similar casting properties, and it doesn't dig into the spool like the braids and get real aggrivating. What it does not do well at all is fish slow presentations. P-line tends to have a lot of memory unlike most mono and on a slow presentation, it looks akin to a banjo string stretched across the water. Obviously, this hinders feel and hookset. It is relatively low stretch and that characteristic allows you to feel your blade turning on a spinnerbait. This is critical with that type lure.
For crank baits, top water baits including top water soft plastic, I use mono. It has low memory and the stretch mono has helps compensate when you pull too hard with a graphite rod against a fish on a crankbait. My choice of mono for the last 4 years has been Cabellas Pro Line. The reason, its dependable and cheap. I know, someone's going to claim its not as well made as the name brands. I don't buy that, I have used it and used it. Out of over 50 spools of it, I have only came across 1 bad spool. I believe that mono basically comes out of the same factory off the same lines for most brands, it just gets a different sticker at the end. BTW: I once got a spool of Cabellas line that had a Trilene sticker under the Cabellas sticker. The thing is, at $5.99 for 1200 yards, you can change often which I highly recommend on any mono.
For worms, jigs, and other slow moving baits, I use that cussed braided Fire Line. When I say cussed, you can't fish that junk long without cussing. If you hang up, you can guarantee the next cast will land there, it will slice you hand faster than a Case knife, and it is extremely hard on equipment like reels and rod guides. It has 2 redeeming characteristics that make it viable otherwise I don't know of a sole who would put up with it. Those are No Stretch (therefore you feel your bait much better) and no memory. Past that it goes down hill fast.
My 4th type is the Mason's line. That's the old fashioned braided nylon that looks as big as a small rope. I use it for 1 thing, shiner fishing in Florida. The 1 and only reason to use it is it can be waterproofed with boot waterproofer to make it float. A real plus on that tactic in the grass. Mono or other sinking lines won't work. There are some people now using fire line for this purpose (it floats out of the box). While the bigger braid does have an advantage of having less of the above problems of Fireline it does still have them to a degree.
Skipper