In reply to Lord of Starkness:
ive been commuting over the winter in summer shoes, two pairs of socks and some planet x overshoes - my experience is cold feet for the first five miles, warm for the next ten, cold for the final ten.
Today ive tried some Northwave farenheit, without overshoes and with normal socks, was coldish but not uncomfortable, with some merino socks, think they'll be good and i guess i coudl put the overshoes over them if it is really cold.
If you arent using overshoes, id certainly get some, although the px ones arent all that great in my experience - i preferred the ones i had before but cant remember what sort they were!