Having spent some time looking for true anonymity, thus far I think the solution is a VPN (they are cheap) that has a solid privacy policy. HMA keeps records and will hand them over to anyone for any reason. I would want a VPN that never keeps anything. From what I have read, some VPNs might have some temporary records of their client's browsing, but those get deleted about every 24 hours. It's an ambiguous specification, but I think falls within the boundries of "good enough".
So then the next question is whether or not the VPN (which ever one you use) passes on, or COULD pass on, the MAC address. There's a secondary conversational thread that has to do with Java and whether or not it's possible for a website owner to interrogate a browser's computer for the MAC. My opinion is that it can, and they probably do. Certainly Law Enforcement does and can. Assuming that it is possible for a computer running Java to deliver the MAC address on demand, does the use of a VPN prevent that? I don't think so.
Another thing to think about/worry about is https://panopticlick.eff.org/, which also raises the question of whether or not the unique, or near-unique identifiers will be passed on through a VPN.
In a more general sense, I think the idea of functional, law-enforcement and government-proof method of anonymous web browsing to be completely under-discussed, and probably under-monetized. Most of the references that I see to it are academic, white-paper style discussions on a theoretical level, and there does not seem to be a simple, easy-to-utilize method/system of web browsing that is specifically designed to prevent nosy and highly technologically developed entities (meaning government) from finding out what people are doing online.
And not for any specific purpose either, but as a general standard of basic human privacy. We don't walk around in public with our junk on display, we don't mail-off snail-mail letters without sealed envelopes and for those same reasons (and many others) I think there needs to be an overtly stated message that the consensus is that government's have no business casually browsing through the communications of the people that they oppress, er-, I mean "govern".
And why beat just the government (whatever/whoever that may mean to any particular person)? Because if people establish a firm line of defense against uninvited government intrusion into their personal lives, then it sets a much higher standard for all other entities that might want your data, such as corporations, marketers, etc... If the government can't have it, Google sure as fuck can't have it either. So, you set the standard high for the most-powerful entity, that might have the most compelling reason to violate your inherent right to privacy, and then you are safe from all other intrusions also. Unless someone wants to violate the Law, which is written to protect you from them, and not written to use you to help make their profits. We have an either/or choice here, and I suggest people pick the right one, or someone else will pick the wrong one for you.
Otherwise, you get what we have now, which is an "evolving" (meaning meaningless) standard that completely depends on who it is that wants the data, for what purpose and at what level of anonymity. Marketers can have "x" data for "y" purposes with a level of "z" anonymity, but the Socialized Medical "community" can have more data, for different purposes with less anonymity, etc... If one predicts where this multiple entity, multiple standards and highly complex and variable equation goes, eventually they can pretty much do whatever the fuck they want with your data, for any reason that they decide, and the standards for your privacy will be handed to you by THEM, in the fine print of some document labeled "Terms of Service", much like the language that you agree to when you use a Microsoft product, or that yearly document you get from the Bank.
They should just dispense with all those words and tell the truth, which would look like this:
Dear Anonymous User,
We can do whatever the fuck we want, and all you can do about it is complain to someone that doesn't even speak your language.
Sincerely, go fuck yourself,
The Invisible Entity that Has Power Over You.
So, when I consider this possible future, and look for ways to avoid it, I conclude that the only way to prevent this eventuality is to simply prevent anyone from looking into anything for any reason. Good, workable encryption and the legal right to use it, with good & workable methods for anonymous data transmission & reception.