I've switched to the plastic cages offered by Kleen Kanteen to fit their stainless bottles (which I also use). The cages are light & well made, with very little friction on reinsertion-while-riding. I've found that they also work well with rigid & semi-rigid plastic bottles. Only downside would seem to be that they handle a limited range of sizes -- my bottles are about 700 ml.
Current behaviour by the weather gods, mean sods that they are, makes this is a discussion for the future: we have our mid-March snowstorm today, although the temp is a bit higher than yesterday's -8 and the NW wind has eased and shifted. I was out on my city bike yesterday for a few errands, first time since early December, and that was enjoyable--cold, but the roads were clear & dry. Forecast is for -17 on the weekend, but happily, it won't be my problem...
J.