OpenELEC is the Kodi distro of choice for lightweight hardware. Last time I looked they don't support ARM hardware though. There are a couple of Linux distros that can be installed on some Android boxes and then Kodi, Myth or some other media software installed. I am disappointed with the Minix X7 but event they have a new Android box out that has slightly better specs. Until ARM video and audio hardware improves dramatically, let's just say I would rather spend $300 on a low end AMD or Intel HTPC than than $150 on another ARM box.