Audiophile quality playback?

All things being equal I suppose the digital output on my mac should sound the same regardless of what application outputs to it, but it does not. Itunes for instances sounds thin and weezy.
I have what I would say is a reasonable hifi system and its always been my intention to get the best from my music. The main gripe being that itunes cannot change the output of the digital device is the music format changes from say 44 to 96. Will songbird make any attempts at this in the future.
As apple don't appear to give a toss about actual sound quality, I hope song bird developers do! We are not all 12 year old kids listening to lady gaga!
Many thanks