Thanks for the replies!
Our first trip to WDW was on our honeymoon in 2000. We were married on Dec 30th, so we were able to see all the beautiful Christmas decorations. We have a brand new baby now and can't wait to take him. If we wait until the first week in Dec, he'll be all but 8 months old. I know he wont remember it, but we sure will! It wont really matter how long the lines are, due to the fact he is so little, there are probably isn't much he can do yet. Luckly the "single" lines are always fast and easy.
We love going in Feb, plan on using that time as a yearly event.
I'll never go again in the summer or fall... way too hot and crowded.