Andrew Breitbart isn't exactly a household name, so his recent (quite young) death may have been largely ignored by most normal media outlets aside from a passing reference.
I was never quite sure what to think about Breitbart, because he epitomizes the exact sort of conflict in media that most people have immediate opinions about but largely don't think about. He was an unabashed partisan who used borderline tactics to advance his cause, but he did to a lot to move and/or create legitimate stories for a lot of headlines during his short career.
Breitbart was behind many things, but he will largely be known for three major events over the past few years: ACORN, Shirley Sherrod, and Anthony Weiner.
His tactics were disdained by the left--and even the major mainstream media--but he didn't really do anything that was largely outside of what investigative journalists have done for decades. ACORN was an old-school sting operation, and while detractors attacked him for editing the footage, the untampered evidence was still damning. Suffice it to say that if a conservative organization had done the equivalent the outcome would have been exactly the same. Likewise, the Weiner scandal was a traditional scoop, and he ran with it.
The case of Department of Agriculture worker Sherrod is a little murkier. He was attacked because when the video was released, he did not release the full context of the speech given by Sherrod to the NAACP. (Sherrod had said during that speech that she did not help a white farmer specifically because he was white; later in the speech, which was not originally included in what Breitbart released, she said she had learned from her experience.) Breitbart, for his part, said that he was not originally sent the entire speech and so was unaware of the follow-up; still, he maintained that the audience's reaction of applauding when she denied help to the white farmer--who, like Breitbart, had not heard the rest of her story--was damning enough (and then claimed the NAACP was his target all along, not Sherrod). While Breitbart was sloppy in this story and the consequences are worth criticism (and with a lot of convenient excuses), there's enough gray area in this experience that I don't think this is a wholly negative aspect of his career.
Breitbart got a reputation as a reckless loose cannon working at the behest of hard-line conservatism, which is only partly true. He helped with the conservative Drudge Report, but he also helped the founding of the Huffington Post (which, to be fair, at the time was not the liberal bulkhead it is today). When he was clearly in the wrong, or had doubts, he tended to rectify them even if it compromised the story--when the source of the Weiner information was cast into doubt, he alerted the media immediately until it could be confirmed. He was also on the advisory board for GOProud, a gay Republican organization, at the consternation of other social conservatives. While his tactics are (gladly) open for criticism, I can guarantee that if the opposing side did the same thing it would miraculously be justified.
On the other hand, he was kind of a jerk--he had no problem calling Ted Kennedy a vile human being the day after he died, and often had no problem throwing out challenges with only a tenuous grasp of reality. An attempt to infiltrate Nancy Pelosi's office was crude and an embarrasing failure, not to mention illegal. Many descriptions after his death pinned him as a more reasonable conservative than he is given credit for, but with an abrasive personality against his opponents that made it difficult to really care. From what I've read, that seems fairly accurate.
Still, I'll say about Breitbart what I say about other obnoxious commentators--I don't agree with many of them and some of them are, indeed, vile people. But you need some of these loose cannons to shake things up and work outside of the moderate, mainstream conventional wisdom, even if for no other reason than to reframe the argument in more practical terms. I don't know if Breitbart, on net, made a net positive contribution to the media, but that doesn't mean I'm not glad he was there.