have a look at the nexII at
http://www.frontierlabs.com/ every player has its downside, this one just has a non silent switch on and off, and rather fiddly battery retrieval.
upside is AA batteries (I use 1800 mA/H metal hydrides) - AAA players are useless for play time.
It plays WMA files, is flash upgradeable, takes microdrives fine, has resume on switch off, and the usb works fine (I use card readers myself).
supplied headphones are acceptable, better sound is always available with an upgrade no matter what player you buy.