For trance synth nothing beat the Nexus 2 by ReFx. It's a rompler.
It's the world first synth right now and the sound design is by Vengeance how's the reference for techno/trance stuff. A bit pricey thought.
I use it on all my tracks, for background etheral, rythm, lead... in fact for a lot of things! Tons of presets that are very usable.
(ps: songs on my myspace have been made more than one year ago, and there's no Nexus on them. I'm rerecording them professionally right now)