Ba,
I'm in need of a new roof soon too. I think corvette brought up some good points. I despise the aesthetics (reflective) of the metal roofs, so I am glad to hear you are looking at shingles.
I've been around the building industry but am by no means an expert on roofing matrial. I think most products will do what they claim unless the manufacturer has a bad batch or you are just simply buying an econo line. IMO installation is the key. A poor foundation will affect shingles as well as improperly driven fasteners that are holding them down. Find a good roofer and you will likely be pleased with the finished roof and the shingles. A converstion with an area insurance claims person may also give you some insight to problem brands?
I also wanted tocomment on your great photos over the years. I may need to ask you some specifics at some point in time. I'm happy to know you are going to those places. You have to get "up top" to truly appreciate.