In my opinion, some ION2 nettop with minimal Ubuntu and XBMC would be better option than WDTV. More expensive, yes, but not that much[1] and definitely provides better experience.

[1] Note that I'm in EU-land, where AppleTV is 120 EUR, which is 160 USD. Acer/Asus/Zotac/other nettop vendors do not have the same problem with currency conversion that Apple does.