Plus, as Billy says above, you can always add bass pedals (which I do, sometimes), an extra manual (ditto), and even VST's to the instrument...so an Arranger is not only an excellent instrument on its own, but a great foundation for a growing setup.

Korg made a really nice 88-note weighted action arranger, the PA-588, that was pretty much a fairly portable stage piano, although I think it may be discontinued.

Ian