Hi,
Surf kayaking is an awesome form of kayaking and has exploded over the last few years. Once you get into a surf specific kayak a whole new world opens up. There are surf kayakers now combining waveski, playboating, surf and squirt moves from big ariels to cart wheels the choice is yours. Not to mention it is super fast and loads of fun... Plastic means heavy, composite means light, for me if you can afford it get a composite surf kayak every time.
In terms of boat you can pretty much use anything however it takes a life of its own when you use a composite kayak. If you are in the UK contact me and maybe we can arrange to meet up at some surf and you can have a go in one.
You tend to sit higher in a surf kayak so at first they seem really tippy, but once you are on that wave..... wow..... Start by trying as many designs as possible checkout the build quality weight and performance, it is a steep learning curve but once you have licked it you will love it.
Good books are kayak surfing by Bill Mattos and Surf Kayaking: The essential guide by Simon Hammond.
Manufacturers in surf kayaks are now
Mega for plastic and composite
www.surfkayaks.com
Valley for plastic and composite
www.valleyseakayaks.com
Murky Water
www.MurkyWaterKayak.com