dmm is indeed in a class of its own, but seriously, there are more out there delay which tgp forums or booteek fellas dont talk much about, those can go to unknown land as well
An example is the moog delay, what it can do, is way beyond more geetar delay, together with the rest of moogerfooger with CV/LFO controlling the setting and inter modulating in between. Its more deep beyond the usual guitar based delay effect.
heh, and of course, if you guys into vst, midi controller and laptop, there are more delay vst which can route and route around until the sound can make a tune on its own.
Delay history?? Duh, seriously, we have not tried enough to talk about delay history lah...