These are my 2 cents, Trash80:
- Milkytracker, a contemporary Fast Tracker II clone available for all major platforms (win,mac,linux... and Android!). It supports the old Amiga MOD format, Impulse Tracker's IT and XM. It's a little bit limited compared to modern things like Renoise (which is excellent and quite affordable, but propietary).
- LittleGPTracker: another tracker with an interface almost identical to LSDJ, but handles WAV samples and decent polyphony. Along with all desktop systems, it runs in the PSP, the GP32, the Dingoo and some other handhelds.
- NitroTracker, a tracker for the Nintendo DS, with no effects, but extremely portable. I use it for sketching some songs on the go
That's what it comes to trackers.
P.S.: The Ardour open source DAW is worth checking, also, but I'm quite unexperienced on it. I've seen some people here using LMMS on Linux (kinda public FLStudio)
Will add some as soon as they come to mind
Cheers!