I'll bet a 32Gb thumb drive will hold more CDs than you'd ever dream of. 32Gb is a popular size but bigger ones are coming out all the time - they're not needed. I've got 2700+ songs on mine and it's no where close to being full - about 12Gb used. Each song takes up 5 to 8Mb at 256kbps sample rate. Just a few of my songs are sampled at 128kbps and they take up less than 3Mb each. Quite frankly, I can't tell the difference. The biggest headache is the volume level of the songs. It's hard to "normalize" the sound levels - not saying it can't be done but I haven't found an easy way to keep all the songs at the same volume.