Onkyo must have gone batshit insane because this fall—September 1 to be exact—they will be releasing a portable media player that lacks a screen completely. This is more of a hybrid between a media center and a portable media player. Hopefully the lack of a screen will cut the price down significantly.
The player appears to support damn near every video and audio format out there, except Apple's beloved AAC and MOV. It also includes many different output cables including composite, component, audio and includes AC power and a car adapter (car pc, anyone?).
Onkyo's Multimedia player with 2.5-inch HDD [Akihabara]