Out of those two I'd choose the Sony NW-HD5, but overall I'd choose a cowon player. Cowons are known for their wonderful sound quality.
ROFL wait the front page it says that the NW-HD5 had best sound quality =\ Well I hear the interface is good too, and its suppodly good looking and small. It seems just right for you.
I am looking for the best sounding mp3 player and do not care about other features other than playing mp3s. My mp3 collection is all high quality VBR and I have Shure E2c headphones, ao all I need now is an excellent sounding player. I'm thinking of buying a new in package Sony NW-HD5 off of e-bay or a new Creative Zen Vision: M. Any suggestions or other factors that I should take into account? Other mp3 players even? Thanks.