From USB hard drive to AV Receiver

For years I've been getting along playing my .m3u playlists (dozens)
of .mp3 files (thousands) from a network storage HDD via a D-Link
MediaLounge DSM-320.

I would have thought that a better way would have been invented by
now. Has it?

The ideal for me would be a device that I could simply plug a USB hard
drive into. The drive would have all my .mp3 files and my dozens
of .m3u playlists on it and the device would allow me to select and
play these playlists.

I've been looking at ads for Asus O!Play, Western Digital WD TV Live
Network-ready HD Media Player, and D-Link MediaLounge High-Definition
Media Player (DSM-510). But the information re audio is very scanty.
I tried searching the manual for the Asus for "playlist" and "m3u" and
got no hits for either.

Does anyone have one of these (or something better) that does what I
want?

Thanks a bunch,

Paula