As one of the first to buy a Korg Karma, I highly recommend it. The Karma function is basically a super arpeggiator, but it uses chord recognition so arranger type accompaniment is also possible. It comes with the Triton sound engine and accepts the MOSS and EXB cards as expansion--so the sound capabilities are quite extensive. Go to www.karma-lab.com for more information. The site is run by the inventor of the Karma function and he provides technical support personally. The Karma is about as much fun as you can have with a music keyboard.

Downsides: a proprietary external power supply. Also, when Korg introduces its new platform, the Karma may seem a little obsolete soundwise.