If you're "lucky" enough to have a HDMI capable GPU and a HDMI slot in your TV, your GPU (may) be able to handle the sound from your TV.
This essentially means that the soundcard and the GPU are already split, so you don't need extra doofers. - So you can just select TV as default, then apply default for for everything and just have the exception of having the headset for vent.
Sound settings in Windows: http://i.imgur.com/99qME.png
Options in vent: http://i.imgur.com/3iNwi.png
(Note that I just have my headset as default at the moment!)