Sorry Luckman, but windows environments (XP & Vista) do not support the rar format natively as they do zip. Perhaps rar is common in many circles, but in this community (and the others that I personally frequent) you will find that the majority of the available downloads use zip. I am not saying all, but most.
I am sure that it just boils down to where we are and what forums we happen to frequent as to which is more common.
