Help choosing speaker/headphone setup for games

[Monkeypillow]

I was originally looking at a 2-channel system with separate components (DAC, amp, etc.), but that's nowhere near flexible enough for my needs. My reasoning is that a high quality 5.1 setup can be used with stereo content with no compromises, but a high quality stereo setup can't be used with multichannel content. That wouldn't allow for multichannel game audio either.

Another thing to consider if I were to go with a 2 channel setup: Many games don't offer much choice in audio output (headphone, stereo, 5.1, etc.). Do soundcards have this flexibility?

Would I be better off with a good headphone setup, or a good 5.1 setup for games? I would like to be able to communicate with a microphone as well.

Good quality, accurate sound is is what I'm after. I'll need a receiver (preferably with binding posts that can accept banana plugs) that can handle all major audio formats and have lots of inputs. I'll also need speakers and possibly a subwoofer. I'll want to use this with headphones as well, so I need that flexibility.

I'm asking for equipment suggestions for an entire system that can handle movies, music, games, and pretty much any other content available beautifully.

This will not be purchased immediately, so I don't have a budget in mind.

I was thinking maybe $1500, but could be convinced to spend more if it meant exceptional gains.