What did you end up getting @ipedro ? Curious to know what you think about the Kanto Yaro's ... they're $100 off right now at Simply.ca, pretty tempting upgrade.
All of the above have their own dolby decoding and amplification. You can simply connect your optical out from AppleTV to any of these and you're done.
Or if can afford it, SONOS has some nice speakers...
If you are not interested in 5.1 and want just 2.0 music, your best bet would be a pair of studio monitors with optical in (e.g. Behringer). They are self-amplified, so no need for an amp. Just keep in mind studio monitors are near field speakers, you don't want to sit too far away from them.
For 5.1, you could get something like the Logitech Z680s I have in my office. I don't think they sell them anymore, but they make some similar setups like the Z906.
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