But I suspect we'll see a few states doing dumb stuff like insisting all wallets have to be "declared for tax purposes"
Many if not most jurisdictions already have such regulations. Whether it's cash in the local currency or bitcoin, you may already be required to report and/or pay a certain percentage of your wealth each and every year to the king, the governor, or to their representatives. I think this harks back to the days where you would hand over a share of your pigs, goats, and grain to the local tax collector. The laws are usually very general -- "anything of value". There's no shortage of real-world examples. See the following links:
http://en.wikipedia.org/wiki/Wealth_tax http://www.artkabinett.com/content/frances-wealth-tax-explainedand
http://www.irs.gov/Businesses/Small-Businesses-%26-Self-Employed/Estate-TaxThis is nothing new or unexpected. From a government's point of view, bitcoin is just another asset to be taxed and regulated.