These are starting to get really popular, going upwards of $200 on eBay, but I havn't seen a good exhibition of what they can do on on youtube, so here it is. This is the older analog omnichord introduced in the early 80s. It has since been replaced with the Suzuki QChord which uses digital...
UltraNova is seriously powerful yet easy to use - and it comes with a software editor. Its powerful synth engine is derived from a classic big-synth: the Supernova II.