Well, looks like it’s time to stop lurking on the ROTJ Despecialized thread and actually try to contribute something.
It seems like you have a few options. Without considering a new AV receiver, you may be able to send a direct audio bitstream via your soundcard’s TOSLINK output with MPC-HC. This bypasses any processing your sound card would do and lets the home theater system deal with the Dolby or DTS encoded data directly, instead of converting it to PCM (or Dolby Digital Live). The only issue is that the bandwidth limit of S/PDIF doesn’t allow DTS-HD MA or Dolby TrueHD bitstreams. For this, you would need an HDMI connection, but it seems your Panasonic unit only has an HDMI out, not HDMI in. If you can live without DTS-HD MA or Dolby TrueHD, you can enable direct bitstreaming in MPC-HC using this guide, although you would have to leave DTS-HD and Dolby TrueHD unchecked when you get to the last step.
If you do want to consider buying a new AV receiver, I would recommend future proofing yourself a little and getting one that supports the (relatively) new Dolby Atmos format and the (brand) new DTS:X format. There’s a fairly comprehensive list of recievers that support these formats here. Keep in mind that the prices there won’t always be accurate, since these things go on sale all the time.
There are a few features that you might want to consider to help you narrow down what you want:
-Price - Obviously
-Number of channels - You can save some money by not going too far beyond your current 5.1 setup, although adding more will definitely take advantage of the “object oriented” approach of Atmos/DTS:X
-DTS:X itself - There isn’t a lot of support for this yet, so deciding you want it will definitely limit your options, although this isn’t necessarily a bad thing. Fewer options makes choosing easier!
-HDCP - Some receivers still don’t support the newest HDCP standard (2.2) for their HDMI inputs, which you will need if you want to view any UHD (4K, 4K/3D) content in the future.
-Upscaling - Some can upscale video content to 4K
-Network features - Some are wireless, others require ethernet. Some have features that are bluetooth enabled, can play internet radio, and can even play audio files over your home network.
-Audessy/Other automatic optimizers - Some receivers come with microphones that measure the output/delay of your speakers and automatically configure your sound for you.
-Total Harmonic Distortion / Signal to noise ratio - Putting too much stock into this is how you end up spending a ton of money on a reciever. Without going into too much detail, these determine the quality of your sound output.
I did a lot of research recently while shopping for a new receiver and ended up going with the Denon S910W. In my opinion, it’s the best “budget” (~$500USD) receiver. I’ve had it for a few weeks now, and it does everything I want and more.