I live in NC and ride year round. Here is what has worked for me:
- Base layers. Thin wicking t-shirts, short and long-sleeve. The one's at Target only cost about $10 and work just about as well as anything, but for really cold days I've got some Craft shirts.
- Long-sleeve jerseys. I've got several in a range of weights but the ones with brushed inner fabric are warmest. Buy what fits, don't worry about the brand names.
- Vest. A vest is one of the most useful clothing items here in fall, winter and spring. I often wear my vest to work in morning, and carry it home in the afternoon in my pack. Mine is a Pearl Izumi but I'm sure other brands work just as well. I would recommend something bright however, like neon green.
- Soft-shell jacket. I held off buying a cycling jacket for a long time on the theory that layering works best. Layering is great, but some of the soft-shell jackets really are superior on cold days. I've tried several but my Pearl Izumi Gavia gets the most use because it fits me well, is very breathable and comfortable in a range of temps, and it's moderately water repellent. It also is very bright (screaming yellow), which I like for commuting.
- Rain jacket. I have had zero luck with rain jackets but will probably keep trying. I've never found a rain jacket that breathes enough to make it worthwhile. Although they keep out rain, they make you sweat so much that you might as well be riding without a jacket. I am tempted to try a Showers Pass Double Century because it is light enough to pack small and only use when needed. Everyone raves about the Elite, but it seems like overkill for NC since we don't get much extended rainy weather.
- Feet. Wool socks and toe covers on my shoes.