Just reading the posts here could make someone acquire obsessive/compulsive behaviour.
I started out thinking 128kbps was a gift from God when I heard my very first MP3 ever, about three years ago (I think it was Liberi Fatali, good start :-D)
Then I switched over to 192kbps because I had some bad experience with poorly encoded 128kbps files. Then I started to feel the itch...
I did my own encoding from music cd's I checked out of my local library, I did so at 256kbps, because, hey, if I have the power to make it happen I'll go for a bit more quality. :-D
Then came along iTunes, it offered a new kind of MP3, MP4 :-D I was excited to find that 128kbps sounded incredibly good encoded in AAC.
But THEN came along the EXTREMELY CHEAP
www.allofmp3.com that allowed me to buy my songs in whatever format imaginable! It was like music heaven to me :-D So now I buy my songs in 320kbps AAC m4a iPod format.
Even with high end equipment that would sound sweet :-)
I won't go further than this though, my iPod is 60gigs and after three years I've only collected 17 gigs of music. So the 320kbps isn't going to be that detrimental to my iPod's HD space. I'm happy knowing I have AAC in the highest possible quality and that I have some breathing room for future high end equipment purchases.
Jam it back in, in the dark.