I know those issues had been discussed already, but how could one react in a five minute coffee-break, when the co-worker responds (standard phrases to go): "But death gives meaning to live. And if nobody died, there would be too many people around here. Only the rich ones could get the benefits. And ultimately, whatever end the universe takes, we will all die, you know science, don't ya?

If they think that we'll all eventually die even with cryonics and they think that death gives meaning to life then they don't need to worry about cryonics removing meaning since it is just pushing the amount of time until death up. (I wouldn't bother addressing the death giving meaning to life claim except to note that it seems to be a much more common meme among people who haven't actually lost loved ones.)

As to the problem of too many people, overpopulation is a massive problem whether or not a few people get cryonicly preserved.

As to the problem of just the rich getting the benefits, patiently explain that there's no reason to think that the rich now will be treated substantially different from the less rich who sign up for cryonics. And if society ever has the technology to easily revive people from cryonic suspension then the likely standard of living will be so high compared to now that even if the rich have more it won't matter.

It does not help to not being signed up for cryonics oneself.

I talk about it as something I'm thinking about, and ask what they think. That way, it's not you trying to persuade someone, it's just a conversation.

"But death gives meaning to live. And if nobody died, there would be too many people around here. Only the rich ones could get the benefits. And ultimately, whatever end the universe takes, we will all die, you know science, don't ya?"

"Yeah, we'll all die eventually, but this is just a way of curing aging, just like trying to find a cure for heart disease or cancer. All those things are true of any medical treatment, but that doesn't mean we shouldn't save lives."

Google alert on "Eliezer Yudkowsky". (Usually brings up articles about Friendly AI, SIAI and Less Wrong.)