Get a Roku and a Popcorn Hour. But the Dunes work great too. You can't go wrong with either a Dune or a Popcorn hour. But the Popcorn Hour boxes cost less. An A300 should do an excellent job. I've been using a C200 for around 2.5 years and it works flawlessly with the HD audio.
Although if the Boxee Box worked just as well with the HD audio, then I would only use the C200 when I need full BD menu capability.
Boxee Box 1, 2 & 3(Boxee+ v1.4.6), PCs(v126.96.36.19996) Boxee TV(v188.8.131.5221)
Server 1: HP MSS WHS (3TB) (NFS/SMB)
Server 2: unRAID1 (39TB) (SMB)
Server 3: unRAID2 (51TB) (SMB)
Server 4: unRAID3 (36TB) (SMB)
Server 5: TiVo Desktop (6TB RAID 5) (SMB)
NAS 1: Intel SS4200-E (4TB RAID 5) (NFS/SMB)
NAS 2: Dlink DNS-321 (1TB RAID 1) (SMB)