The new HDMI 2.0 spec should(?) be in receivers by next year, current HDMI chipsets can only handle 4K video at up to 30Hz. I'm sure that AVRs with "full" 4K capabilities are forthcoming.
ht Panasonic 60" ZT60, Monitor Audio: Silver RX6, RX Centre, Radius 90HD; Martinlogan Dynamo 700, Marantz SR5006, PS3, Oppo BDP-103D
2ch Sony KDL-32W650A, Sony BDP-S1000ES, Marantz PM8004, JVC T-X3 tuner, Monitor Audio Silver RX1, REL T3, Apple TV, Peachtree Audio DAC•iT, Sennheiser HD598
lr Panasonic 50" ST60, Sony BDP-S5100, Apple TV
pc Energy CB-5, Audioengine D1, FiiO A1