So I've been spending months -- whenever I think of it -- ripping my entire CD collection onto my new BIG drives, with the idea being that it's done once and for all. I strarted ripping them through iTunes using the AAC 128 or 256 kbt format. I just upgraded DAP to an iTouch (2nd gen) and got some Shure SE530s, which got me thinking . . . if I am really doing it once and for all, shouldn't I do it in a lossless format so I never regret and have to redo. I bit the bullet and starting redoing the hundreds of CDs I'd already ripped, with hundreds more to do after redoing those. I then got to thinking that I should really do some experimentation and figure out it it's worth it. I ripped the same album in both AAC 256 kbt and Apple lossless and listenend to chunks of tunes again and again side by side. I did blind testing. perhaps it's just me, but I really can't make out a difference. (shure se530s via iTunes on dell inspiron E1505). Is AAC really that good or do I have to listen harder? Thanks for any advice.