Having had teams that were half-remote before, and all remote now, doing lots of hangouts seems to fill the remote-feels-weird niche pretty well. Just having long conversations in chat tends to not be productive, but you need chat. Something like Slack is a good choice if you can't get everyone on IRC. Somewhat still wanting for better "whiteboard simulator" type options. Ultimately not having an office not only save…
Yes, you do the Video calls and you've got HipChat and email. But there's something about being there down in the muck with the rest of the team that builds cohesion, camaraderie, and enthusiasm. I say this as someone who doesn't like crowds or lots of noise. It's also really easy to lose the pulse of the group being remote. I can't easily tell how morale is, what the team's general perception of our future is, and I can't head off issues that would have been obvious in person from 180 miles away.
Perhaps some of this is exacerbated by being a remote Co-founder, but I wouldn't do it again if I had the choice. I wouldn't hesitate to hire the right remote developer, but they probably wouldn't ever enter management or be a partner. You really need to be around each other because of all of those side conversations that happen outside of the meetings. That's where the best brainstorming, dreaming, and bonding happens.