For your purposes, I would look for waterproof nylon or similar pants (not all nylon pants are wateproof), wool or fleece pants, fleece jackets, and waterproof shell jackets (check the tags). If you are buying used clothes, look for name brands. Off brand stuff can be found new at bargain prices. Look at sites like Sierra Trading Post for deals on name brand clothes. Also the outlet sites for stores like REI. Use the links on this site to visit our sponsors-many of them are starting their end of season sales.

The whole "cotton is bad" premise is misunderstood by many. Cotton works well in hot, dry weather, it holds moisture and helps cool you down. Cotton fabric can be heavy though, so jeans are a bad idea, imho, in any conditions. It is not a good insulator under any conditions and is not waterproof (unless treated), so it should be avoided as an insulating layer or outerwear in wet or cold conditions. Cotton also works well and many consider it superior to high-tech fabrics in very cold weather (sub-freezing, where it really doesn't get wet) as outerwear. It works well because it is windproof and breatheable. But that is a specialized use for deep winter only.

Wool is a good insulator, even when wet, but it is heavy. Fleece is polyester. There are various weights and cheap fleece jackets are available almost everywhere. I have an inexpensive Columbia jacket I have owned for at least ten years. I wear it all the time in town at least several times a week and have done so ever since I bought it. I have worn it camping, skiing, snowshoeing and just walking around. It still looks good.

I've never used silk. My base layer is Capilene from Patagonia. I bought my original 2 pieces in the mid 80's and just bought a new expedition weight during their half price sale-it was still $50, but I expect it to last as long as my others have. Merino wool is an alternative to synthetics. Never used it, but looked at some at Patagonia. People who have it speak highly of it. I also wear synthetic briefs, not cotton.

Don't forget, you will also want hats (fleece beanie or balaclava) and gloves or mitts. wool or synthetic lightweight gloves or liners and then insulated, waterproof outer mitts or gloves. Also, get synthetic or wool socks, not cotton, for winter and cold, wet weather.