All Amazon MP3's are 256kb, and excellent SQ IMHO. Equal or cheaper than iTunes on everything, much more limited selection however. But it's a dream with 1-click ordering ... I buy a lot.
This is just for pop that is not critical listening. For serious stuff I agree with everyone here that it has to be lossless, and I use EAC to make WAVs. (My wife thinks it's hysterical when I say "I'm going to make WAVs").
No compression there, but although "lossless is lossless", as Orcin says, I worry about the player's firmware which has to decompress, decode and D-A-C in realtime ... if the firmware programmer took shortcuts (I'm sure Apple is perfect, but with the others who knows, so many firmware revisions on some of them) maybe little glitches creep into the bitstream from one of the compressed-but-lossless formats?
I'm probably being paranoid, and I bet I get flamed, but I'm sticking with WAVs on my non-iPods that support it.