There are a lot of articles out there about this subject but I find the 'best of lists' usually contain a weird pick of kayaks and I suspect these lists mostly reflect whichever manufacturer wants to advertise its models the most.
That being said, I want to offer my two cents for whomever that is lost in the big world of kayak models. Before you arrive at the seakayak model being best for you there are already some questions you need have answered, like which kind of kayaking you want to do. But if all your answers point to the seakayak, meaning you want to kayak on flat water then maybe I can help you with some pointers. First lets take a look at hull design, I found this article by Joseph @ Austin Kayaks very helpfull.
Second the choice between PE or fiberglass. I prefer a decent PE-kayak over fiberglass because of the higher durability and lower price of a PE-kayak. Naturally fiberglass has benefits over PE but the advances in manufacturing technology in recent years has closed the gap between PE-models and fiberglass models significantly.
One of the reasons I see to still buy a fiberglass model for touring, is because it's more beautiful then a PE kayak. But when you hit a rock or scrape it against a concrete wall of a channel or if you drop it while you are putting it on your car it won't look beautiful much longer.
Another benefit of a composite kayak is the stiffness of the frame making it more responsive and less prone to drag then a PE boat. But while touring and during camping trips it won't be that big of a difference.
Lastly you get a lot of talk about the possible speed difference between a composite kayak and a PE model making it easier to get more miles out of a gallon of muscle power in a composite boat. While this is undoubtedly true, I find it isn't that big of a difference, after a day of paddling you are tired no matter what boat you spend it in.
That being said, you are welcome to buy a glassfiber model by all means, keep in mind that you are going to have to be a bit more careful to keep it in good condition.
Okay, no more about that, I don't think it's possible to find a boat who does it all. There are always some compromises you got to make. Do you want to make relaxing multi day camping trips in comfort on bigger rivers, lakes or the sea? Best choice is a comfortable, stable, bigger expedition kayak like the Scorpio MV or HV depending on youre size and how much bagage you want to take with you.
I wanted a kayak that is fast and fun to handle even when it's empty so I chose the scorpio LV. However, I find it a bit small for multi day trips and not agile enough when playsurfing is required. It can do it all, but you need to work a bit harder then sitting in a Delphin LV for example. When the Scorpio LV is completely loaded for a camping trip it sits rather deep in the water and you will be wanting to use your spray skirt to keep your cockpit dry.
So compromises are needed as you can see. If you got the money, I would by a big kayak to go camping(scorpio HV) a small crossover playboat/creeker (pyranha Z-one) to explore small rivers and whitewater, an agile, faster kayak (P&h Delphin) to play in the surf and the P&h Valkyrie for training and daytrips. Although you can go camping with the Valkyrie and the Delphin too. So I would say, buy a kayak that is best suited for what you want to do the most and compromise when you get out of its comfortzone. Most of the time however you will see that the boats comfortzone is larger then yours. Happy Kayaking everybody!