I'm surprised to hear responses that seem to be anti-net-neutrality. In my mind, it comes down to one thing - let ME (the end user) be empowered as to WHO I want to contact, and HOW I choose to contact.
I see it as important as the US mail system was and is. Imagine if the USPS started to delay the delivery of letters, to "unimportant" persons, while delivering "important persons" mail immediately. If that happened, I would raise hell. People deserve to have their mail delivered, regardless of who they are or what address they live at, with a best-effort service.
Note also that the USPS allows for different classes of mail, with different priorities, and at different costs. I have no problem with that, as it is content-neutral and addressee/addresser-neutral. ISPs will eventually differentiate traffic, and perhaps charge different prices for different amounts of traffic for various traffic classes.
I have no problem throttling P2P traffic, it would be akin to "bulk mail", in a way. In fact, like junk mail, it also takes up a majority of internet traffic.
But I do have problems, if ISPs start to prioritize various web site traffic over others. (Akin to a violation of addressee-neutrality of mail.) For example, imagine if your ISP served up TomsHardware faster than Anandtech, on purpose, because TomsHardware cut a deal with your ISP.
I likewise have a problem, if ISPs start to actually FORGE traffic. It would be like the USPS sending a letter to my grandmother, asking her to stop sending me mail, but with my handwriting and return address on it, because she sent "too many" letters to me within a month.
Net neutrality is very simple once you view it in the same context as the postal system. It's primarily a political, not a technical, issue. How traffic gets prioritized or throttled doesn't matter. It DOES matter, on what basis said traffic is handled differently.
That's the crux of the matter, IMHO.
Edit: For an extreme example of NON-neutrality - what if black people had their postal mail delay for two weeks, while white people had their mail delivered immediate.
That would seem wrong to you, wouldn't it?
What if it were done on the premise that, statistically speaking, white people paid more in taxes (because they generally were more successful in society, etc.), than black people. The assumption is that they are therefore paying more, and thus deserve better service. (For the purpose of this example, assume that the postal service is paid for by tax money.)
Does that still seem so wrong, once the economic argument comes into play?
For the 'net version of that, replace white people with HTTP users, and black people with P2P (BitTorrent) users, and replace taxes paid with profit made off of that user.
Not so clear-cut anymore, is it?
What if we take it even further, and black people's mail is randomly discarded, once a postal person get busy sorting mail.
What if sending pornography through the mail was illegal, and the argument was made in support of the discarding, that most mail that black people send to each other was porn?
(Analog: All P2P traffic is illegal, therefore ISPs have a right to interfere with said traffic and drop it here and there.)
Would you support, destroying someone's mail, just because they were a black person?
Would you support, interfering with and denying traffic just because it uses a P2P protocol?