Basically, this tells me that registration is more important than the circle-c.
You make an important point about registration. Yes, while it is true that your work is automatically protected by copyright laws the very moment that it is created, in order to get full and maximum legal protection, you must register the work with the US Copyright office and pay the filing fee of $30.
The good news is that this $30 fee is not per item protected but rather for each submission. For example, professional photographers protect themselves by registering their photographs with the US Copyright office. They don’t pay $30 per image, however. What they do is submit page after page of contact proofs - and you can get a lot of contact images on a sheet - and then copyright the entire submission as a whole which extends protection to each and every photograph that happens to be included.
The reason you will want to have registration is because it enables you to collect attorney fees as well as statutory damages. Without registration, all you can collect is any monetary losses that you might be able to prove the the infringement caused you or any monetary gain that it can be demonstrated that the infringer made from use of the copyrighted work. For most of us who engage in the creation of intellectual property as a hobby and on a strictly amateur basis this can be important because the ability for a hobbiest to prove monetary loss might be, I suspect, rather difficult. And if the work is infringed by another amateur - for example, a non-commercial personal website - chances are that the other person will not realize much, if any, monetary gain from the infringement.
One thing that is important with registration is timing. Your best protection is to have your work registered prior to publication - but, for practical reasons, that is not always possible. According to one website that I have bookmarked which I suspect is a bit out of date, as long as you submit the work within 90 days of publication, you can be protected retroactively from the date of original publication. For work that has been published prior to 90 days, my understanding is that, while it can still be registered, it is a bit more difficult and the standards for eligibility become more difficult the further back the date of publication was.
The bottom line is, for most of us, to claim damages from an unregistered work is not very practical. The actual damages which might be awarded will very frequently not be enough to cover the cost of the attorney fees, assuming one can afford such an attorney to begin with. And even with registration, if the infringer is someone who does not have much in the way of assets, there is not really much that you can do other than to stop the infringement - you can’t get money from someone who doesn’t have any. On the other hand, if your registered work is infringed by a commercial enterprise, it might be worth your while to take the matter to court if your case is strong enough. You might end up with your attorney fees paid for and far more money in your pocket than what they would proably have had to pay if they had only licensed the material from you in the first place.
Here are a couple of links on the subject to sites that have helped me understand the issue better:
http://www.peterkrogh.com/copyright/main.html (this site is about copyrighting photographs)
http://www.keytlaw.com/Copyrights/benefits.htm
http://www.keytlaw.com/Copyrights/cheese.htm