I agree... it depends on what you want.
Personally, I would skip January. The crowds are low, but it's not a big enough advantage over November (as long as we're not talking about Thanksgiving time) to make up for missing the holiday season stuff.
Late April is nice if you like swimming and water parks. Actually, though, I would pick May over late April, to avoid the grad night kids. We had some pretty annoying experiences with big mobs of them in the parks, cutting lines, etc. (Oh, our one friend is up there in front of you, so the other 49 of us are going to join him.)