I'm considering switching from alloy to carbon wheels - just a question regarding that & brakes. Would I need different pad materials from the standard sort of pad material (or even a whole different type of brake mechanisms)?
Most carbon rim manufacturers like zipp and enve recommend a brake pad of their own. However, there are typically several pads that will work. Most of these pads are designed specifically to work well on carbon rims. Regular brake pads from alloy rims should not be used on carbon.
Zipp recommends the following pads for their rims:
So, I would check with the manufacturer of your rims to see what pads they recommend and stick with those, otherwise you could be voiding your warranty on an expensive set of rims.
Leonard Zinn (author of Zinn and the Art of Road Bike Maintinance and owner of Zinn Cycles) recommends against using regular pads on carbon rims. See the following from the article in velonews:
I can say from personal experience that standard brake pads on carbon rims are grabbier, giving louder, less predictable, potentially dangerous braking, and they wear faster, even melting down rapidly at a critical moment on a long, fast, tortuous descent, leaving you with no brakes at all. Furthermore, conventional pads on carbon rims are down right scary in the rain, making for unpredictable braking until the rim is wiped clear of water enough for them to grab.