2nd this one. A quick access to 'consumer' sound adjustments just by a (multiple) press of the button would rock. Like Bass-Treble-loudness-balance. Hold it down for a second would default back to the previously selected EQ/balance/loudness preset.

EQ is nice, but as long as it isn't possible to tie the presets to songs or playlists, it's just too hard (and dangerous) to operate while driving.

Cheers, J.