Babies will stick to what they know and what they're used to. If you feed baby food at room temperature, they'll keep eating it at room temp and may even fuss a little if it's warmed up. It really goes for the milk too. If your your baby milk that's cold (with chill taken out of course), then they'll take it that way.

My little one likes his milk warm too. We were at a restaurant the other day where they absolutely REFUSED to help heat the milk - they wouldn't microwave it (which is fair enough) but they wouldn't even give me a bowl of hot water to stand it in - "health and safety" they said. In the end I ran a bowl of hot water in a sink in the bathroom and stood it in that for 10 minutes. Usually I find public places are more than happy to help though.

A friend, when it came to weaning her children, fed them jars at room temperature. They soon got used to this and it saved her having to worry about heating them up when out and about. I think she had a period where she had to slowly get them used to warmer food, but she feels that the benefits outweighed the disadvantages.