Finally, there's the point (unpleasant to contemplate for some) that income inequality can't increase beyond the level it has already reached today without massive and unpleasant social consequences, some of which may be non-obvious side-effects of the drive towards a security state strong enough to protect the elite. By some estimates, 20-25% of the labour employed in the USA today is guard labour, work devoted to preventing the poor from expropriating the rich.
Just got around to reading the whole thing; it's highly recommended.
It's filtered through Stross's latest major topic for discussion -- the viability of space colonization -- but it goes from the launchpad of "Is there anyone alive RIGHT NOW who could afford to be involved in that endeavor?" to a very thorough and well-thought-out analysis of the difference between the 99% and the 1% (though he notes, as we have here, that it's more like 99.5%/0.5%, or 99.9%/0.1% as Brent had it).
For the top bracket, food, clothing, shelter, and transportation are effectively free, and education is trivial; however, they have concerns that the lower brackets don't (like the passage Sei quotes above) and, ultimately, Steve Jobs died not due to any limits on his own resources, but due to limits on the capabilities of modern medicine. (And, okay, if recent headlines are to be believed, he may have made some poor decisions along the way, but that's quibbling; Charlie's overall point is correct: sooner or later, that cancer was going to kill him no matter what he did.)
EDIT TO ADD: Another great thing about Charlie's blog is the comments section; it's at least worth skimming here. It bounces from topics like how much better off the poor of today are than 100 years ago (not that it's awesome to be poor, but, as noted earlier in this thread, you're not likely to die of starvation in the US -- or polio, for that matter), to how the workplace would look if nobody actually had to be there, to what true global economic collapse would look like.