Another downside that gets me sometimes is that I miss shared whiteboards. I'm a pretty visual/physical thinker. It's nice to have a whiteboard you can both see. We mostly supplement w/ screen sharing or SMSing iphone images of sketches. It works but it's not ideal. One of the things I'd love to work on someday is tools to make remote-work better/easier. For instance, I think it's rad that many of the 37signals folks work remotely and build tools that scratch that particular itch.