I keep a copy of Chrome around since it has Flash built-in. That has let me remove Flash from my system, with significant battery life improvements. But I don't trust the browser... they have integrated the search-bar with the URL box, meaning every URL I type gets sent to Google for inspection just-in-case it's a search query. Google knows enough about me, thank you very much.
For everyday browsing, I used to prefer Firefox due to its stability with many tabs and windows open, and some user interface details that I liked. Plus, it's available on several platforms, and I go between different computers every day and found the consistency appealing. But the latest versions have been buggy, and Firefox (and Chrome) doesn't support some of the best features of Lion, such as the double-tap-with-three-fingers which brings up a dictionary and thesaurus for whatever word you're tapping on. That is a flippin' marvelous feature.
So, after Firefox-on-Lion annoyed me one time too many, I started using the Safari browser, which had previously left me cold. But I'm loving it now. The two things that delight me most about it and have made it my everyday browser are (1) the aforementioned integrated dictionary/thesaurus, and (2) READER MODE!
Reader Mode deserves a paragraph of its own. I send a lot of articles around to friends and colleagues. With 90% of these, the little "Reader" button appears to the right of their URL. This means the Reader engine has succeeded in parsing the article's format to differentiate between what's content and what's fluff. Clicking the button brings up a nicely formatted and much more readable version of the article, missing ads and other distractions and formatted to be easy on the eyes. And, most of the time Reader will be able to load in all the pages of articles that would otherwise require clicking "next"... "next"... "next"...
AND the best part is, hover your mouse towards the bottom of the Reader page and up comes a little menu, which includes a mail icon. Click this, and boom: up comes a nicely formatted email with the entire article cut-and-pasted, with a link to source and even the subject line filled-out with the article title and source!
Unbelievably wonderful.