Seriously folks, it's a red herring, an issue created to make sure that one party has something to fight the other party over. If you want to sack the rich, have at it. Just don't pretend that by taking that position you are doing anything at all for the national treasury. Or poor folks, for that matter.
In the larger picture, many technologists view the state as something of the past. Tens of thousands of people make their money simply because computers are hooked to each other over wires. It has very little to do with national budgets or policy (yes, you can throw out a bunch of silly nonsense about national broadband policies and such, but let's get real: this economic activity takes place in all sorts of various scenarios.)
So if you are the type to sit around pining away your day, thinking about all those super-rich folks and how good they have it, I'm sure this will be a fun article for you. If, however, you are concerned with public policy -- and the fact that in the US, at least, the majority of people do not even pay an income tax, yet vote on the rates for the rich minorities (gee, wonder how that will turn out?) then this is all so much posturing.
I don't feel a need to slam Buffett. He's a patriotic citizen who means well. Smarter guy than me in a lot of areas. I'm just not sure that this article has anywhere near enough merit to have 500+ points on HN. It offers no solutions, only rehashed populist tripe. If you want to set the income tax at 95% of all money made over a million bucks? Have at it. It's not important.