It would be nice to have an equalizer on the N900 as I like to listen to the unit mostly without ear/headphones and find sound a little thin but clean.
Did try symfonie but uninstalled it as it distorted the sounds too much.
When listening thru h/phones I choose either the set that came with the N900 or my Sennheiser 300s. Both seem to give reasonable bass without boominess. Sounds fine with Grado 225s as well!