Lots of reverb and echo and a stereo enhancer for strings and guitar sounds.
For lead lines play/program/record or whatever, with for example, a Minimoog VST sound and then copy and paste the notes into a different synth piano roll, move it up or down an octave or whatever you think sounds best, use a stringy sound with the second synth and pan slightly left and right with a stereo enhancer for a mega lead line.
You can hear this sort of thing in action at my myspace site at
http://www.myspace.com/pjtmusic with the track Zeon