guga
10
that’s the thing which got my sitting on a chair for hours 
the first time i was in front of an XT i didn’t really know where to put my hands on (well, on the knobs, that’s for sure
) but the friend who showed it to me, played some patches that really amused me (not sure this is the right word to use here) for their ever evolving/never ending sounds (especially those lush pads, mmm); well, shortly after that visit i got my (first and only) XT and was blown away from its power
orange or black, with tapered knobs or pulse-like ones doesn’t matter, if you get the chance of getting one, do it! don’t hesitate 
worth have a look at the Q as well, another bad ass synth which i still regret having sold

also: for less money you could get yourself a Blofeld… now, it doesn’t come with all the extra features you have on the XT (40 odds knobs, sub out, analog in…) but you do get the Waldorf sound, and with an external MIDI controller i.e.: BCR2000 you could get pretty close to it, just a thought 