Safari on iOS 5 hasn't changed that much in terms of obvious new features. It's a little bit faster at loading a rendering pages, and with twitter now built right in to the system, sharing links and pages is now easier that ever. But my mostest favoritest feature is the Reader function, which intelligently consolidates the main text of a web page or story into a sleek, easy-to-read overlay. You can then adjust the size of text to your liking. All the ads are gone, the random spotting of miscellaneous tables, pictures and other junk also disappear. As someone who reads a lot of news on websites from my phone, the Reader function, which actually had its first appearance on the desktop, finds a perfect home as a new little button right in the address bar.
Here's some screenshots--a page of the NYT before and after: