...and my first impressions are; "this is how the browser wars are supposed to be".
Theres an array of built in features - gimmicks, if you will - like the mandatory email and IM stuff, but the one I'm most impressed with is the "Hotclick" dictionary/encyclopedia/translate feature. Double-click on a word, or right-click on a phrase, and you get a menu allowing you to look it up or translate it.
Pretty cool, I thought. It sounds almost like Microsoft's "SmartTags", but it's been implemented properly and won't cause half the controversy.
Oh, and it's only 3 Megs to download (Microsoft - whywhywhy 17MB for IE6???)