It probably does not make much difference. If you find that you have greater difficulty in colder air or warmer air, then you can make the decision.
grasshopper, I got a new humidifier about 6 months ago and I love it. It's called the Venta AirWasher and you can get it online at http://www.venta-airwasher.com/. It doesn't leave any of that white residue that some humidifiers do, it's really quiet, easy to care for (no filters to mess with, just fill it once a day and clean it every 2 weeks) and best of all it keeps the humidity up (and I live in Vegas, that's not an easy thing to do!).