We gave dd one from Ikea for her birthday and she loves it. It was only $15 and well worth the cost. It has the chalkboard on one side and dry erase on the next. The bottom has a place for the large roll of paper. (Also sold at Ikea).
DS has the Melissa & Doug easel. It is great! No complaints. It's chalkboard on one side, with an open trough-like tray. The other side is whiteboard (dry erase) with a divided tray (for paint, crayons, brushes, etc.). It has a wooden dowel for holding a roll of paper in the middle. You can also adjust the height of the boards so that it can grow with your child. It is a little pricey, though. That's the only drawback. It's great quality, though. DS got his for his birthday, so we didn't pay for it, it was a gift. I hear great things about the Ikea one too.
Re: Recommend an art easel for ds.