The Xiosynth is a damn good bit of kit. They're one of the few manufacturers with good-sounding digital filters, in my opinion - the Xiosynth and the (fairly similar) A-station really have got quite a natural sound.
Plus the Xiosynth gives you a simple USB mike and line input, and line output. It's a lot of noise for 200 quid. The build quality is a bit lacking, but that's about the only criticism I'd have. Oh, no, wait - Novation, are you listening?
I SAID, NOVATION? ARE YOU LISTENING?
Some firmware to make it multitimbral would make it rock more than anything similar has ever rocked before.