BpmDj has some very slick visualization features:
But its designed to work with two soundcards hooked up to an actual DJ
mixer, and doesn't really work so well without such a setup.
I tried to package 3.2 a while back, but I discovered its hardwired to
run out of a single "windows style" directory tree thus needed some
hacking to make it packagable, which I never got around to. Maybe that
got fixed. Its up to 3.6 now.
Someone needs to hack Jack support. And MIDI control binding. :)