XM is too limited for my tastes, although I've got quite a few modules in XM format. Fast Tracker II was my first tracker, but I later found ScreamTracker 3 and it was better interface-wise (even if S3M is more limited than XM, the program handled much better and was easier to use), then of course, the far superior Impulse Tracker, then later Modplug Tracker, which is what I use now.