ATV2 Speaker set up

I know there are a few threads on this already, but I just wanted specific info for my set up.

I have an ATV2 hooked up via HDMI to my TV. I want to buy some Audioengine A2 speakers that will work using the TV, ATV2, and to stream my music to, via the ATV2, with the TV off. How would I do this?

ATV2 - TV via HDMI
ATV2 - Speakers via optical with 1/8" jack converter?
TV - Speakers via RCA

Would that be how I set it up?

Thanks for any help!

After a bit of reading the Audioengine P4's seem more suitable, although they are not powered and so would need an amp. Can anyone recommend a set of powered bookshelf speakers for about £100-120?