I tested my own ripped CDs a few years ago, and decided that 256 sounded better than 128, but there was no difference any higher. I ripped everything at 320 just to make sure. I always assumed it was my cheap earphones (Apple earbuds and £30 Senheissers), but it turns out few people can. That makes me feel better about being cheap! 
Have a listen yourselves here:
http://gadgetshow.channel5.com/news/flac-vs-mp3-does-it-really-make-difference
Have a listen yourselves here:
http://gadgetshow.channel5.com/news/flac-vs-mp3-does-it-really-make-difference