Electrostatics for techno/trance? Boy, that's a good question. Electrostatics are very quick, clean and transparent, but they may not offer you the slam (especially in the bass) that a lot of techno requires. My STAX actually have equal (if not better) bass extension then my Sennhesiers/Grados, but don't have the sheer grunt and impact of either. Personally, I don't miss it, but everyone is different.
And because they are so revealing, they will probably spotlight any sonic nasties in the recording (which may also not be a good thing - some of my techno recordings are not very good).
Grados seem the natural choice for high-energy music like techno (or rock). They do dynamics and impact like nobody's business. And no, like Gluegun states, Grados certainly are not bass-deficient.
If you can, audition some electrostatics, Grados and Sennheisers (and Beyer and AKG, etc). Your ears will be the best judge of what's right for you.
Pretty funny, though - I'm thinking of the engineers at STAX having a collective stroke picturing someone listening to trance on their delicate 'stats!