Mallet already mentioned this in his random thoughts for 3/28, but I wanted to discuss what I thought was a really nice scene near the end of Ultimate Spider-Man #107. I'm referring to Spidey standing up to Daredevil's little group and definitively stating they will not kill the Kingpin.
That seems like an important step for Peter. Too often, he's intimidated and freaked out by what's going on around him, which is understandable to a certain extent. He keeps getting in the middle of weird stuff, which is also usually life-threatening, and that can leave you feeling uncertain, making you easily mainpulated by someone who seems to understand the score. Whether it's Nick Fury, the Black Cat, the Kingpin (working through Jean DeWolff), whomever, Peter spends a lot of time jumping through hoops for other's benefit. Now he's put his foot down and said "Forget it, we aren't doing that. I'm on board with stopping the Kingpin, but we'll do it the right way, I don't care if you think it's a naive way of viewing things."
It shows the growth he's made as a person because in the past Peter has responded to the Kingpin by acting rashly, trying the violence route. Early on, he thought he'd bring Fisk down, so he sneaks into Fisk's penthouse to get some dirt on him, without bothering to do his homework about the building first. Result, he gets beaten, fried, unmasked, and dumped out a window. When Fisk started backing that political candidate on the anti-Spidey platform, Peter tried swinging right over and attacking the Kingpin in the middle of a gala party. Result, Peter goes SPLAT! on Fisk's nice shatter-proof glass, providing amusement for the patrons, as he slides down the window. And there's the whole thing with DeWolff being in Fisk's pocket, and getting Spidey to go after both Hammerhead and the Kangaroo. Spider-Man certainly has reasons for wanting Wilson Fisk's head, but he's not going to resort to killing, and even though his threat was to snitch them out to Fury, he won't let the other guys do it either. He wants to bring Fisk down the right way, get the information on his illegal dealings, disrupt them, try to make Kingpin nervous and reckless, so that he can be easily caught.
I think this is an inevitable consequence of all the crap that resulted from the Ultimate Clone Saga, and Peter finding out that all that was due to the machinations of one Doctor Octavius. When you find out that this one evil fellow has been jerking you around for months, it probably spurs a desire to assert yourself a little more, to minimize the potential for that happening in the future. We saw it when he not only got his job back from Jonah (though that was somewhat a compassion move by Jameson), but negotiated more hours and a small bump in his salary. He didn't back down, but stood there, and politely explained the situation to someone who frequently intimidated him in the past, and it worked out.
It would have been nice if this had newfound confidence/independence had lead to Peter talking things out with Kitty a little sooner. But he is still a kid, regardless of how many times he's been through the wringer, and matters of the heart aren't easy no matter how old you get, I suppose. And he did try to sort things out with her this issue, so that's something at least.