Chrome: Like the name suggests, the Awesome New Tab Page extension adds a new New Tab page to Google Chrome. The result is a Windows 8 Metro UI-inspired new tab page that's fully customisable with apps, widgets, bookmarks and so on.
The good: It's very customisable. You can rearrange, move and remove anything you like. The extension itself is also extensible with widgets, though currently only one non-stock widget is available (this weather widget). If you're interested in creating your own widget, you can get started here. It's also nice that you can make the Chrome bookmarks bar show on the new tab page by default -- something that used to be built into Chrome that I used regularly, but which Google removed in the most recent iteration.
The bad: The tab page takes a little too long to load. This is probably the biggest problem right now, though it could easily be improved in updates. It's also still a little rough around the edges.
Overall, though, it's easy to set up and use, looks nice, and with the option for widgets, has a lot of promise. If you've already got a beloved new tab page replacement, let's hear about it in the comments.
Awesome New Tab Page [Chrome Web Store]