picked up a Klegg MediaShare from Fry's Electronics for $130. AvsForum thread over here. hardware-wise, it has DVI and optical audio out, along with component connections. for content, you can install an (optional) harddrive or just plug into a network. its not a UPnP AV client, it just recognizes folder shares. so it can see the folder shares on my Windows Home Server and ReadyNAS. it has wireless (g) built-in (optional on 360) and comes with a remote control. i tested it wired and without a harddrive.
it does a couple things i wish Xbox 360 could. first, it plays Div3 files (360 and PS3 dont). it also plays mpg1 and mpg2 (360 only plays mpeg through MCE). it also supports DVD files (IFO, VOB, ISO) ... with DVD menu and subtitle support ... beautiful. you can jump to specific time, bookmark, slow play, and repeat a video segment (360 doesnt do any of that). finally, it can successfully play the DivX 5 files that the 360 had audio stutter problems with. its also supposed to support video files with multiple audio streams, but i dont have any files to test with. finally, it seems to be firmware updateable.
it doesnt do so good playing mp4 files (which 360 does beautifully), a number of mine would play audio only without video. it also froze up when i was fast-forwarding an mpg file and stopped responding to remote commands. the video kept playing, but i had to manually cycle power to get it to come back. was also hoping this might support video playlists, but it doesnt look like it.