-It’s fast.  It’s really, really fast.  This is the most important thing.

- New tab bar is different. Makes sense, but will take getting used to.

- MobileSafari-style stop/reload buttons.

- Search bar uses Google Suggest and includes search terms found on the page.

- Top Sites is great.

- CoverFlow is great.

- New Location bar dropdown is interesting. Not quite the mess of ugly that is Firefox’s “AwesomeBar.” I, for one, and glad it only completes URLs and not title tags.

- They renamed the SquirrelFish Extreme JS engine to the more public friendly “Nitro” engine. Chickens.

Update:  WebKit developer Mark Rowe confirms in a posting to the webkit-dev mailing list:

Nitro is Apple’s marketing name for WebKit’s JavaScript engine, code-named SquirrelFish Extreme.  There are no difference between them as the names both refer to the same thing.