The purpose of navigational tools and cues is to allow the user to get where they need to be. The best type of navigation is the ones where the user doesn’t even realize they are using it. The user shouldn’t have to figure out how to use your “cool” new nav.
An example of bad navigation is ESPN’s “floating nav”. I did an entire post specifically on this feature here: ESPN Floating Nav Text.
An example of good navigation has to be Amazon’s. The site is incomprehensibly huge, yet a user to able to get to any item with a couple of clicks.
This may be a personal preference, but any nav that changes when you move the scrool wheel on your mouse is too distracting. If the entire page changes because I’m scrooling down a few lines it is very disconcerting. Please give me a way to turn that function off.
In Summation- The best navigation is one your user never notices.