Personally, PSP Go hands down has the best design for handheld.
It really showed the PSP as a true gaming device (when slid open) and multimedia device (when closed). It has a nice small size that actually feels portable in your pocket and I love that it hides the main buttons/d-pad/thumb stick so it protects it from getting particles inside when it's in your pocket.
I would love it if the Vita had the same re-design treatment as the PSP Go, the media feature would be alot better with a touch screen.








