If you want to play different media on your TV, there is no way around a corresponding media player. This can either be a complete HTPC or - if you already have the data on a NAS - a media player. The best known representative of this genre is the second generation AppleTV (Black). Unfortunately, the restrictions that Apple imposes on its devices are also included. Luckily, AppleTV has jailbreaks just like iPhone 4s and iPad 2, so that the playable formats can be drastically increased - a full-fledged media player is the result, the iOS features are preserved.
On the other hand, there is the possibility to use a panda board to put together a media player yourself, which runs either with Android 4.0.x or Ubuntu. Advantage of this solution: since you can rely completely on open source software, you are free in terms of configuration and possibilities. This increases the amount of work that has to be done until you have a finished system that can play multimedia files. Interestingly, free solutions are more expensive. The cost statement:
- AppleTV 2: 119,-€
- HDMI cable: ~4,-€
- Total: about 130,-€ with shipping
- Pandaboard: ~175,-€
- power supply unit: ~12,-€
- RS232-USB adapter: ~16€
- better antenna: ~5,-€
- USB mouse and keyboard if necessary
- Bluetooth remote control if necessary
For the Pandaboard you can buy linaro.org ready Android binaries as well as Ubuntu + XMBC. Ubuntu has been adapted for ARM processors (like the OMAP4430 on the panda board), also the hardware should work well. So there should be no problem to get the Pandaboard running with its 1 GHz dualcore ARM processor. Still, it's the effort of the setup that kept me from using this solution.
So now for the first time an AppleTV of the 2nd generation comes into the house, which is equipped with a Jailbreak (seas0pass) and then probably unlocked with aTV Flash (even if it's not free) for file formats like .MKV. If that doesn't work as desired, I still have the option to order a Pandaboard.
As a further alternative there are ready-made Android TV boxes, for example the myGICA ATV1200 with Dual-Core CPU and Android 4.1.2 as basic operating system and XBMC support.