No offense to everyone who clearly has strong opinions here, but I think the focus of the argument should not be on Assange himself at all.
It is a simple fact that at some point in time, someone, somewhere, WILL (not maybe) leak information of this magnitude. It just happened to be this man at this time. If not Assange, someone would have decided to pull a similar stunt in the interests of freedom of speech/protection of rights/etc. etc. etc.
The question that I think this topic should have asked from the beginning is: Is the person who decides to be the vanguard of this controversy a hero or villain? This removes all the personal attacks and character flaws of the man/woman in question, and focuses on the idea of disclosing or hiding information deemed as secret.
To dive into this issue, I would say that the person in this position is in fact a hero because he had the guts to stand up for what he believed in, and against such an imposing and giant foe. This does not mean that his actions or field of interest (leaking sensitive information) is included in my labeling him as a hero - this avoids a value judgment of the actions themselves, for a hero can be a hero even if he does evil; he is simply a champion to those who share his beliefs.
So, now that I am done with talking about the person who becomes the focus of the conversation, I can address the actual concern that I have on this topic: the use/abuse of the term "secret" and it's functionality as a label. If you have seen any of the leaks, or even read many of the reports on the subject you will find a lot of information that truthfully doesn't matter much at all. However, these tidbits are classified as secret, and are therefore just as important (according to their label) as other things that were leaked, things that actually do have a large impact on current politics/relations. My issue is that I feel the government is too easily using the label "secret" as an out; a way to avoid making something public, simply due to a fear of whatever backlash that new information will create. Instead of dealing with the problem, they declare it a secret and avoid having to be transparent or anywhere near the chopping block or public opinion.
So, ultimately, I think the actions taken to expose these secrets was a good action - not because it broke legal stature, and not because it has the potential to hurt out national security or position in the world (because again, this was going to happen at some point and the fallout will be the same, just different dates and facts). The reason I support it is because it is a show of the abuse of "power" that our government utilizes simply to make their jobs/lives easier. We all do this in every profession - who doesn't want to be able to do their job efficiently and well and deal with the important stuff? But in such a public domain, and one that shapes so many lives/ideas/beliefs, I find that cutting corners for ease of use is unacceptable. Furthermore it is the path towards corruption in all potential forms.
So if you choose to argue over Assange's actions, whether it be to leak information or to enjoy sex without a rubber, please go forward with gusto! But know that you are only arguing over the character of a particular man, not the issues of secrecy, information, or transparency.
I apologize for the length, but I felt it necessary to make my point clear.