I've never understood the whole "Bitcoin transactions are anonymous" theory. If anything, the Bitcoin model promotes a sort of hyper-transparency. The anonymity today lies in the fact that no one knows what wallet is linked to what person/business. If it becomes a widely-accepted currency among retailers, it would eventually become trivial to look at any given wallet and see that $x was spent at Amazon on this day, $x was spent on groceries, so-and-so filled up their gas tank at this particular station, etc. You can shuffle coins between wallets to obscure your tracks somewhat, but you're still broadcasting every transaction you make to the world.

I think this is horrible for the average person, but would be a great thing to implement for transactions where you would want some form of accountability, like political donations, charities, investments, taxes, etc. If I give my money to some organization, I can use the block chain to see that they're using the money they receive for exactly the purposes I expect them to be using it for.