I haven't been following the advancement in flash based MP3 DAPs (except the iPod nano). My requirements:
-Flash based
-Small and compact size (like Samsung/iRiver flash player. The nano is thin, but the height is too long for my taste)
-512MB-1GB
-Tactile buttons, no touch strip or surface. I want to be able to control the device in my pocket without having to take it out or looking at it.
-AAA battery
-USB2.0
-Good battery life (preferably at least 24hr rated)
-Instant on, yet still maintain good battery charge when off. I don't like DAPs that need to "boot-up," especially for a flash player. When I press play, I want the music start playing.
-Pure UMS file transfer for music.

Those are my requirements. I don't care/need other features. Any suggestions?