20,000 songs? Not nearly enough. $24.99 a year? Way too spendy. Unlimited and $20 a year? That's a little better, at least, and that's what Amazon just moved to. Taking a step up from its previous $20 for 20GB plan, the former bookseller is now letting new subscribers get any amount of storage they want for that price -- unlimited for .mp3 and .m4a files, anyway. Naturally this means any songs pur
