The Garmin name and state of the art GPS devices tend to go together synonymously. Buying a Garmin, you can rest assured that regardless of the model, you are receiving a quality product that will last. For Aviation, any Garmin GPS units will be the best value for your money. If money is no object, the Garmin 496 is the best model currently on the market. The maps on the 496 have superior detail to the 396, and it has features like XM weather updates and warnings for both terrain and aerial traffic.
If money is a concern, any Garmin GPS unit will provide you will the tools necessary to stay safe and plan out your flights, although buying a model before the 296 lacks the modern and updated feel.