The only thing that i can come up with that is different is the MP3 as you said and that the 650 has cool graphics and screen savers my friend has the same deck. As for best buy if u can live without the cool graphics and screen savers go for the 550. They are exactly the same deck without 2 features woo hoo jk If u can burn cds and dont need the MP3 go with the 650 its only like 15-25 dollars more on ebay so ur decision //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif