Hi AT, no nothing in particular, I think that the stock square waves are enough.
Here's a very quick attempt for Rapture.
It's not a clone, just relying on memory and personal taste
- two square waves, slightly detuned
- set to multi just to get some additional fatness (I know, this is cheating
... )
- generous amount of portamento
- quick amp attack - but not zero in order to avoid clicks and help the portamento itself
- LP4 filter almost completely open, good amount of resonance in order to add some air
- very light amount of tube distortion before the filter
- hall reverb
https://dl.dropbox.com/u/3980034/rapture_lucky_man.prog hope you like it
Ciao
Francesco