I just wish a bunch of well-known publishers would get together and agree on _one_ solution that they'd all add to their site.
It's just a matter of adding a widget on their article pages. They already have large readership. It could kick things off and maybe get over that network effect cold-start issue.
They could add a nice bounty like "make a first payment and don't see ads on our site for a month". Or similar.
A solution like this could be a good candidate because it's neutral. With Flattr or similar you're encouraging that particular middleman. However I think to inspire confidence in publishers they'd need to prove that this solution will have strong support for years to come (which is always unsure with open source projects).
EDIT: To be clear I'm mostly thinking of micropayments to news sites. The strategy is less clear when talking about electronic commerce in general.
The value for users comes from the ubiquity of the payment system. Nobody wants to transfer money into the wallet for infrequent or one time buys.
They seem to have the right idea and might get the implementation just right, but if they can't get the momentum, it's all for nothing. I really hope this takes off.