(this review will appear in Issue 2 OF Make magazine)
Elgato's EyeHome is my favorite new toy. It's fundamentally an iLife-to-audio-and-video converter: plug an ethernet cable into the "input" side of it, and then connect the A/V outputs of your choice (RCA-jack analog or SPDIF audio; video is composite, component, or S-Video) to your home theater system (in my case, a crappy TV and an ancient stereo). The EyeHome communicates (HTTP over port 8000) with an EyeHome server installed on a Mac in the network, requests content, and plays it back. It works just fine over 802.11g. The unit's tiny--8" x 8" x 1.5" and less than a pound--and, because it's fanless, utterly silent.
The content it plays can be EyeTV-recorded TV shows, music from your iTunes library, video files, or photos from iPhoto albums. There's also a web browser of limited utility.
For the things I most wanted to do with it--listen to music and watch movies--it works marvellously. I can hear some compression artifacts in the audio (a tinny high end and some overall murkiness), but it's still quite listenable. The picture viewer is at least as good as my DVD player's JPG viewer. I paid $149 for a refurbished unit, and it's a steal at that price. At $199 list, it's still an excellent value.
It's not utterly magical. In a perfect world, it'd take my high-definition captured digital TV, downconvert it to NTSC, and play that on my TV. It doesn't (EyeTV NTSC captures work fine). Its inability to play purchased iTunes Music Store tracks or Quicktime movies is a bit distressing, but if you're willing to put up with some transcoding to get your video into MPEG or DivX format and your audio into something without DRM, it's not a big problem. For $149, though, I won't complain: I adore my EyeHome.