Good design. Not much different in placement. The animated slideshow of the top content is a step up from the previous static picture. The large icons make it easier to find content you'd be interested in.
That being said, there's room for improvement. The information on each module of the front page differs in importance depending on who's viewing it. It would be amazing if each user could move each module around and get rid of unnecessary ones, it would mean a layout which is unique to the user.
Games / Movies / Audio / Art / Channels:
The overall designs are good. The genre system is great for looking for relevant content and Newgrounds didn't have anything quite like that before.
Each of the pages is rather bare, though. Above each genre section should be something interesting or useful. Games should have P-Bot saying what version of Flash a user has and a small demo game to play. Movies should have a slideshow of featured content or full byte-size content for the user to watch presented by P-Bot. The Audio Portal should see the return of A-Bot playing all of the newest top-rated tracks. The Art Portal should show I-Bot with a digital canvas with a random piece of high-rated art being displayed in nearly full scale. Channels should have a picture of The Crew, newly updated for 2012.
It's only as useful as long as it's continually updated. There also needs to be some sort of Newgrounds themed calendar art, better navigation, and the ability to click blank space in a given date and view all of the data such as daily winners and submissions from that day.
Needs much more content.
It's a good start on getting all of the site information into one place.
Much more useful. Now .swf, .fla, .swc, .psd, .jpg, .gif, .doc, .txt, .htm, .xml, .zip, and .tar are all supported. Technically, this means any file may be submitted because any of them can be archived as a .tar file.
The new system looks great. Hopefully it will make collaboration much easier.
Much more compact. Everything has its place now.
The stats page is an interesting addition, but it would be better to simply line all of the stats up along the left side of the main user page.