@Paul: can't really see why you would bother with this when you can have a mac mini
The trouble here *might* be the mismatch between your HDTV's panel resolution and TV overscan issues. Sure, you can buy a DVI-to-HDMI cable, but that only gets you the connection.
The direct way around this is to use the TVs VGA/DVI port. One of the most overlooked features in an HDTV--at least here in the States--is that the HDTV's VGA/DVI port (if it even has one!) isn't always the full resolution of the panel itself.
I consider myself quite versed in all of this and I still missed the fact that my JVC 46" 1080p set's VGA port only drives the monitor at 1024x768. My friends with newer Sharps and Sonys have ports which drive the full 1920x1080.
So if you know your TVs VGA port can drive the panel at the full 1920x1080, then a mini is 90% better.
I say 90% because the appleTV is utterly a consumer component. No tinkering needed for anything. No keyboard needed, nothing. The Mac mini, since it's a full computer, has some edge cases where you need to be sure you have a keyboard and mouse around "just in case".
I've had an appleTV since they first came out in the States. I sync NOTHING to it. I've got a Mac mini in the other room with 2TB of storage attached to it and that STREAMS everything to the appleTV.
It's brilliant. I just sit down at my TV and all of my media content is right there, accessible with a 6-button remote.
It makes no noise and it's small and out of the way. I hardly remember it's even there. I use it far more than I use my iPod.