Most Versatile
Cuisinart Cordless and Rechargeable SmartStick
This thing is so good you'll be writing sonnets to it after a while. It purees baby food right in the pan or in the bowl, the measuring cup, the jar you microwaved it in. Whatever.
It also makes the creamiest, dreamiest, mashed potatoes. You control the level of puree, so it doesn't need to be overdone. However, because of the way the blades tilt, it's also a great whip, meaning mashed potatoes are light and fluffy, and whip cream comes out perfect every time.