The only way for US residents to refill an AllOfMP3 account - without having a Diner's Club card - is to use an XRost prepaid iCard.... And the only way to get one of THOSE is to go through their Visa/MC processor, "Click & Buy". At the moment, AllOfMP3's got a special going on where you get a 10% bonus for using an XRost "card" - and apparently a 20% bonus for ANY refills at the moment - I don't know if that's on top of the XRost bonus, or what.
So, it's cumbersome to fund an account with them; this is the result of the RIAA's raging snit over a music site that doesn't encumber music with obnoxious DRM, and which actually offers a variety of codecs to suit the user.
I love AllOfMP3 because I can get music in Ogg Vorbis format. My own feeling is that this site is how a music download service SHOULD work - it should be my choice what the codec and bitrate is - allowing me to pay more for higher quality, if that's what I want.
Personally - I absolutely loathe the iTunes software - even leaving aside the DRM issues - which means the iTMS isn't really an option. I find it mind-boggling that one can't even browse that store to see if they have anything one might be interested in without downloading and installing iTunes. *bleah!*