My favourite is the original ayu-mi-x: in particular Poker face, Trust and Signal (tracks 1, 8 & 9) sound SO good with volume turned right up. If you like frightening the neighbours and enjoy the old songs, ayu-mi-x I is the one to go for.
Like Moe-loves-ayumi says you also get a second CD (effectively free) with 13 AO tunes too.
Course, you could always trial them all by grabbing some mp3s to help decide
