Me. I've been wiping/drying the top of the window glass and the rubber seal as I leave the car on an evening, made a bit of a difference as long as it hasn't snowed.
if you use some gummi-pflege on the door seals should help i have used it on my z3 and now on my z4 and works well http://cgi.ebay.co.uk/Einszett-Gummi-Pflege-Rubber-Care-Stick-100ml_W0QQitemZ320464667185QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item4a9d2ec231
iv found when i open the door on my roadster the window drops down and then doesnt pop all the way back into the seal, but its easily resolved by winding the window down a little and then all the way back up
Warm water - DANGER as the rapid expansion of the glass could cause it to crack. I use Ggummi-Pflege on the seals and seems to work on all but the coldest of days.