You hit the nail on the head with OpenMPT, gotoandplay. As someone who started with FT, transitioning to OpenMPT felt weird. I still haven't gotten fully used to it yet, as I haven't done much with sampled sounds.
Look around and see what you like, but here's a few I would recommend:
OpenMPT
LSDj (Gameboy)
FamiTracker (NES/Famicom)
VGM Music Maker (Genesis/Mega Drive)
SunVox (This one has been ported to many mobile devices, but you will have to pay for it on some of them. It's free on PC.)
GoatTracker (C64)
Raster Music Tracker (Atari 800)