Who makes the best 88key midi usb weighted keys keyboard

I have an M-Audio Keystation 88.
Loads of programmable knobs and sliders. The feel is pretty good, but a bit heavier than my upright acoustic piano.

For piano sounds I use Pianoteq, and am very happy with it. Kenchan discusses various software pianos in his V-Piano in ken's music room.. thread. I don't agree with all of his views and conclusions, but it's probably a good starting point for you.

Regards
Andy