i had this same problem when we went to paris before christmas.  i was damned if i was going to wear ugly shoes in paris!  i ended up getting a lovely pair of black ecco boots that came up the calf.  looked great, stylish, still warm and comfy to walk in even all day!  i would find yourself something like that instead of the cowboy boots.  they'd also be lighter to carry in your suitcase that cowboy boots.  dress 'em up, dress 'em down.  i say all this while we are currently sitting at -29C and i wear nothing but my uggs.  the ugliest of the ugly, but also the warmest :)  have a great time!