That's one thing that (i think) most economists do agree on: the first best tax scheme is a land tax scheme - on the value of the land, not the value added (by building houses, apartment buildings, or skyscrapers).
This is politically infeasible and measuring the value added is difficult, so the second best most economists push for (i think) is a sales tax which at least doesn't discourage productive behavior.
The income tax, on the other hand, is just a terrible idea.
Many economists do support the land tax, but think it is too low to support government functions. I think a better criteria is - restrict the government only to the extent that you can support with a land tax, since a land tax is basically the approrpriation of a positive externality(civilization all around you)
Tangential, but a subject of some local interest:
Why Bitcoin will fail by Avery Pennarun. "The sky isn't red." Thesis:
I'm not sure I buy these and am not competent to evaluate his claims on 3., but would like others' critique.
L019: Bitcoin P2P Currency: The Most Dangerous Project We've Ever Seen by Jason Calacanis. A rather more enthusiastic viewpoint of the project:
The actual text contains many more caveats than the eye-catching selection of points above.