In the meeting:

• Stay calm and maintain professionalism. Don't show fear. Just try not to show any emotion.
• Take notes about anything that seems relevant to your layoff. PRO payouts, when your final day will be, any severance pay you might be getting, etc.
• Ask about COBRA benefits. But don't go ahead with incoming those unless it's necessary over the next few months, because they usually suck ass (cost a lot).

And some general advice:

• Look up how to, and then tee up, an application for state unemployment benefits. As soon as you're laid off officially you can pull the trigger on that.
• Get personal contact info for anyone at your job who could be a good professional reference.
• Get copies of any work-related certificates that might be useful in future jobs.
• Try to find the good tech recruiters in your city or region. There's usually at least one among all the crappy ones. Ask colleagues/friends if you don't know where to stay. Avoid the sweatshops like Accenture unless absolutely necessary.
• Update your resume on LinkedIn and start looking for new opportunities. But I wouldn't flip your status to 'looking for work' because you'll probably just get flooded with spammers and scammers. But look on the down-low yourself.
• Determine which subscriptions you can cancel to save some money, because if you get laid off it's belt-tightening time.

Good luck!