Whatever you can afford, and feel comfortable in. For me, that meant something with chammy (synthetic), lycra fleece, and then merino wool tops. But that's just me - some people never ever wear lycra.
Natural fabrics all the way. Not into this gore tex sprayway naff naff nonsense. Have some dignity. wear a nice suit and get flourescent cycling clips.
i really fancied some of the howies ventile stuff but couldn't justify or afford £350 on waterproofs. dickies are pretty good in the wet-they dry surprisingly quickly.