I have gapless playback now
After trying all of the above, here's what I did. I do not use any 3rd party plugins.
In DirectSound output settings:
* Move 'Buffer-ahead on track change' to 1000 ms
* Enable 'Remove silence at beginning / end of track'
* (Edit) Move the slider to -60 dB to prevent soft/silent intro's/endings being chopped.
That's it! no more gaps between MP3's! (Didn't try CD's yet.)