I know I am a little late to the discussion but my dd6 (and new DYS) went through a big puzzle phase when she was two.

She lacked a bit on fine motor skills at the time, so some of the cardboard pieces were tough for her to "lock in" - even if she had them in the correct place.

I found the Melissa and Doug puzzles and Ravensberger to be slightly better, due to the quality of the pieces. However, our most successful find was the "foam" puzzles by edushape.

I think the ones we have are 54 pieces. DD especially loved this one, as it coincided with a a big interest of hers in the 50 states.

http://www.amazon.com/Edushape-8470...-and-games&qid=1299622391&sr=1-2

We also have a world map, a water scene and a jungle scene.

I have recommended them before to some people who did not enjoy them, because the foamy nature of the pieces allows a child to easily put the wrong pieces together. This was not an issue for us. YMMV.