I own a pair of 598s as well and love the sound signature. For a closed back pair I've found that the 439 is as close as you're going to get. They're considered the step down from the 449, but I consider them a better pair and I know alot of other think so as well. In addition it has a...

 I agree with PurpleAngel in terms of the MP3 player commendations. I still own and use a Clip Zip and have previously owned some of Sony's recent Walkmans. Both are impressive devices, though the fact that the Clip Zip is so small and expandable (up to 32gb) means I usually recommend it over...