My Santa got me a pair of the 3-in-1 sets. I really love these because of how much design work has to go into them. They take some number of pieces and can make 3 distinct constructions, with minimal extra pieces.

In the sets I got, I can make: fast car, pickup truck, skid loader, propeller plane, hydroplane and helicopter!

I really appreciate this gift, but the only trouble is what to make first!