Just to clarify:
NAS = Network attached storage
-> Basically a large harddisk that can be accessed via the network
CAN include a MEDIA SERVER that MIGHT BE based on DNLA
-> a programm running on a PC or NAS that offers files to other systems (TVs etc.)
A USB stick (or external USB disk) should always be formatted NFTS (windows user, sorry) to support large fils
(sure not if USB stick is 4 GB or less).
NFTS is not recognized by all TV, though.
SO, I'd follow the advice and use a hidden box that communicates with a NAS (NOT a media server though, due to performance issues, tagging of files).
I use a Western Digital Live TV HD that accesses my files on a Synology NAS (had a Buffalo Terastation NAS as well, that was good, too).
The WD Live has a USB port, too...
Best regards
Ralf
Living Room: Beosystem 4, Beolab 7-2 (Center), Beolab 9 (Fronts), Beolab 8000 (Rears), Screen: Sony KD-85XH9096
Home Cinema: Beosystem 4, Beolab 7-4 (Center), Beolab 9 (Fronts), Beolab 4000 (Rears). Projector: Sony VPL-HW55
Home Office: BeoVision 11-46, 4 x Beolab 3, BeoCenter 9300 (BLC 1611/ML/NL)
Bedroom: Sony KD-65XH9077, Beosound Essence MK II with Beolab 6002 and Beolab 11 (all white, wall-mounted)
Dart Room: BeoPlay V1-40 on floor stand
Guest Room: BeoVision 7-40 MK IV, Beolab 7-2, BeoSound Ouverture