I still think that a flat rate per month is the way to go. $14.99 for 30-days - get what you want. Then it's up to you if you'd rather wait twice as long for a 256kps mp3 over a 128kps or a 8:00 minute song over a 4 minute one.

One thing to be careful about, with these WMA services, they can limit your ability to burn and some will even "expire" your songs once you end your membership. Newer protected WMA's only play in windows media player.

That's why I'm really likeing emusic.com. They encode with LAME VBR, membership can be as little as $10 a month if I sign up for a year (free 2 week trial to try it out) and when I cancel, I get to keep my songs!