A4 X7. Known in the US as the OCZ Equalizer. Mine's the notebook version, which is smaller than the normal version. This is exactly why I like it - I use claw grip - most people use palm grip, so a smaller mouse is a big advantage. The form is absolutely perfect for a claw mouse, so is thumb button placement.
My only con would be that at 2000/2500dpi, the mousewheel LED flashes different colors.
My only con would be that at 2000/2500dpi, the mousewheel LED flashes different colors.