How good is your hearing? If it's fucked then there is a good chance you wont hear the difference
Seriously, don't copy all your CDs at that quality to ipod if that's how you are going to listen to them most of the time.
I do that (maybe not so low) but only listen to my ipod when outside or in random mode. Like now. My hearing is also shot & I really can't tell too much difference as I can't have my music too loud with these paper thin walls.