Okay... time to separate Wheat <---> Chaff
Rights vs. registration;
If you have to register to exercise a right, it is not a right.
Not true. You have to register to vote.
Why couldn't we require registration of journalists, bloggers, etc.?
Because Congress is not charged with a duty to manage the press or media and thus does not have explict powers to do so. Congress does have an explicit duty to organize, arm and discipline the militia, however.
Restrictions of Rights:
The government may impose reasonable restrictions on the time, place, or manner of keeping or bearing arms, provided the restrictions are narrowly tailored serve a compelling governmental or societal interest.
This is strict scrutiny. Limitations on a right must
be narrowly tailored to serve a compelling governmental or societal interest, which generally means that the limitation has to be shown as the LEAST intrusive method of limitation. In most cases, it requires some overt action to be limited -- like yelling "Fire" in a crowded theatre, or inciting people to lynch a prisoner.
Thus, we get limitations on rights for compelling reasons;
- Felons - have shown by serious crimes they don't obey our most important laws.
- Minors - recognizes that mental processes of children are not sufficiently developed to comprehend legalities, ethics and the seriousness of their actions.
- Mental paitents - recognizes that ajudicated mental paitents do not comprehend legal, moral or ethical matters and/or follow laws, presenting a danger to the public and/or themselves.
Each of the above meets a simple test that is easily determinable. Is the person a felon? Are they a minor? Have they been declared mentally impaired? In the "yelling fire" example the question is "does a fire really exist?" and if not, the speech is not protected.
Why does this not mean that, potentially, the whole Second Amendment couldn't be suspended "in the interest of society?"
The right cannot be suspended or abolished without an amendment. Declaring the right void to all citizens would be to discard the amendment process which exists as a large hurdle in making sweeping changes.
Fees & Taxes:
What would be the difference between registration (assuming the law allows collecting an 'administrative fee') and a poll tax? And was the poll tax ever actually ruled to be unconstitutional?
There would be no difference between an "administrative fee" imposed on any right and a "poll tax". Poll taxes were ruled unconstitutional around the turn of the century IIRC.
Requiring registration is probably constutional, but requiring even a nickle fee is not. I'd even go so far as to say that requiring you to pay postage to mail your forms would be unconstitional.
Amendment X: If it ain't in the preceeding, the feds CANNOT do it. Trust me, registration of firearms isn't in there.
Not quite. Congress is authorized to make laws, rules and regulations to carry out its duties under the constitution. One of their duties is
To provide for organizing, arming, and disciplining, the militia, and for governing such part of them as may be employed in the service of the United States, reserving to the states respectively, the appointment of the officers, and the authority of training the militia according to the discipline prescribed by Congress; (USC, Article I, Section 8)
Thus Congress can make laws and regulations pursuant to this duty. As part of their "arming" duties, it's quite possible that Congress would require information on the types of arms in the hands of the militia in order to make decisions about training, organization and the types of ammunition needed for training or deployment.
so? cart then horse, of course registration would have to come first. but again, that doesn't mean it will lead to confiscation or that there's even a high likelyhood of it. 
