I'm looking to get a keyboard in the $500 - $700 range. Will be using it mainly for recording purposes (so midi capabilities needed), but also for live performances from time to time. I'm mainly looking for something that has realistic sounds, so not Casio. It seems liek Roland and Korg are the top brands. I've come across various terms when searching on the web (arrangers, synthesizers, etc), and not sure what the difference is and what I would need. I'm just used to calling it a keyboard. Any recommendations? Also had a question about keyboards...is it possible to expand a keyboard's instrument/voice selections by loading additional VST instruments, and use those instruments (when not connected to a computer)?