If you're looking for the lot at a great price, the WD TV Live could be the one.
It offers a responsive interface very similar to the PlayStation 3's XMB menu system. It's compatible with Samba, NFS and Bonjour network shares, along with UPnP servers such as media centres and PlayOn.
You can also watch YouTube videos, Flickr images and music from Live365 and Pandora.
In terms of file formats, the WD TV Live's Achilles Heel is Windows Media files - it choked on WMA9 Pro and WMA9 multi-channel files as well as WMV files with 5.1 sound tracks.
It also refused to play RMVB files. It handles ISO, VOB and Blu-ray well, although you can't access the menus.
The WD TV Live starts at the beginning no matter which file you click, with seamless transitions between VOB files. It also supports Dolby Digital and DTS audio.
The WD TV Live offers 16x fast forward speeds with a helpful progress bar, but is fussy when it comes to network performance. It choked on some files from a 10/100 Samba network drive, yet played them via Samba from the Gigabit media centre.
Windows 7 digital television recordings can be played via UPnP, although most looked pixelated (we're told a patch is coming). Vista digital television recording offer better performance, and it plays Vista recordings via Samba.
If you're not interested in the Apple TV then the WD TV Live will most likely meet your needs - plus it's small enough slip in your bag on holidays.
The only hesitation would be if you're looking to stream Windows 7 Media Center recordings, or have a taste for high-end Windows Media files.