This is what I use.
For gaming:
Audio Channel: 6/8 (depends on game, ime, as to which works better, 8 seems to be fine for most)
Sample Rate: 44.1khz (sample rate of the files you are listening to, and games almost always use this)
Analog Out: Headphone/FP Headphone
Dolby Headphone: Tick (DH-1 usually the best for clarity/positional audio, through DH-2 sometimes nice for singleplayer depending on the game, e.g. I find Skyrim great with it. DH-3 far too reverby and busy for me)
7.1 Virtual Speaker shifter: I don't think this helps much under Dolby Headphone, but you're welcome to experiment with it
Nothing on under any of the other tabs, and GX button and SVN off.
For music:
Audio Channel: 2
Sample Rate: 44.1khz or higher (sample rate of the files you are listening to)
Analog Out: Headphone/FP Headphone
Dolby Headphone: Untick (Though, if you have good quality source material, e.g. high bitrate lossless or CDs, you can use DH to your preference, otherwise I find it decreases quality noticeably with MP3s. This is really personal preference, though, so use it if you think it sounds better. I personally find listening to jazz FLACs/CDs to be much better with DH on.)
7.1 Virtual Speaker shifter: off (same as above)
Dolby Pro Logic II: off (You can try play with it, but I found it didn't make things better for me)
If you're listening to music in pure stereo (no DH) then I'd get a crossfeed plugin for your music player. I find this really helps with the fatigue and headaches that you can get from using headhones for a long time when listening to music.
As for the Echo issue with voice, try using the AEC or VocalFX tabs.