The guys in the winter cycling forum have bootie threads like we have bag, iro and hipster threads. They know their stuff way better than us fair weatehr riders. Check out some of the threads there. Much more information than in here. They give full on reviews for like every peice of kit they own.

I normally don't use booties. Instead I wear neoprene cycling socks over my gym socks and then put on my mtb shoes. I find this to be way better sealed and warmer than booties in general. That being said, I have 2 pairs of booties. 1 pair is the MEC pack cloth ones linked above. I used them in the rain with my commuting mtb shoes, but its the paddling socks that keep me warm. I also have a pair of descente neoprene booties that fit my sidi road shoes perfectly. They are pretty tight shoes so I can just fit a pair of ski socks in there before it gets so tight it cuts of the circulation to my feet making them colder. On colder days and longer rides I pop a chemical warmer in the toes between the shoe and the booty.