I found this awesome desk at a yard sale a few years ago. It is made of sturdy wood that has held up well to my son climbing on it. The desk has a wide base and is low to the ground which makes it perfect for kids 3 and up...my son was still using last year when he was 8 (although he is small for his age). It is virtually incapable of tipping over because of the wonderful design.
My son loved it because it has several places to stash his stuff. There is a canvas pocket that velcros to the back of the chair. There is a hole on the right hand side of the desk that holds one of two plastic cups (for crayons or pencils). And there is a shelf under the chair too. Another great feature (to him) is that the table can be drawn on with chaulk. And finally, (because my son is left handed) this desk is great for both left AND right handed kids. Although it is one piece, the desk part extends all the way across the front.
If you are looking for a good, sturdy desk for you child take a look at this one. It's great!