I don't think there was ever a limitation on the meta description. It is recommended that you keep it to 255 characters or less. I use meta descriptions that easily fall into the 200 character mark. As long as the most important stuff is in the first 140/160, you're good to go.
I think the Longer Snippets are a great feature. And yes, I also think that there will be less click-throughs for some sites. < Those who fail to optimize the areas that Google is extracting the Snippet from.
We know Google use meta descriptions in many instances. Maybe it is time to stop listening to all the SEOs out there who say that this meta description is of little value. As of this moment, it just became a very important element in the new Snippet equation. Not to mention site structure when viewing source. What exactly do you have sitting right after that <body> element?