I use Boxee Boxes, a Roku2, C200, PopBox, and Xtreamer. My local content is mainly BD ISOs stored on my WHS, unRAID, INTEL NAS, and Dlink NAS. I mainly use my Boxee boxes since they have the best combination of local and online playback. but since getting my Roku2 I find I'm using that more for my online content now, and I'm also using my C200 more lately for playback of my BD ISOs since there are any audio dropouts from the advanced codecs.
But as my local content grows, a quick UI with quick access to the content is more important. I'm only using built in features of my media players for aggregating my content.So my Boxee Box is still the easiest to navigate all my content since it is much faster and presented better.