I usually listen to music in Dolby Pro Logic 2: Music as well.
I like the simple signal for the surrounds as an additive component but for some recordings can sometimes collapse the sound a bit into the centre.
Sushi's suggestion of widening the center channel (receiver settings) works well.
My preference would probably still be for a completely 5.1 channel dvd-a or sacd recording if i had such equipment and music.

"Those who preach the myths of audio are ignorant of truth."