SoniqCast in now shipping the new Aireo, which they say is the first portable MP3 player with integrated wireless (802.11b). Like the Nextway D-Cube, it also has a 1.5 GB capacity and FM reception and broadcast.
Another novel feature is a slot for SD (secure digital) media cards. It's not yet clear if you can play music stored on the card and/or transfer files (photos from a digital camera, for example) to the player. But in any case, it's a step in the right direction for transforming MP3 players into all-purpose, portable file storage devices.