TMT, PowerDVD and WinDVD require a protected path for lossless decoding without downsampling to 48khz/16bit. That said, most movies are 48khz/16bit or 48khz/24bit and it's unlikely that you will be able to hear the difference. They will still sound better than the core audio that is being decoded by MPC-HC's internal decoders.
The only ASUS card that supports protected audio is the Xonar and it requires TMT.
Any other DirectShow application (NextPVR, JRiver Media Center, etc) can be used but, like MPC-HC, will require you to set up the LAV filters.