Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Safari. I used Firefox on Snow Leopard but since it doesn't support Lion's new features I ditched it. Safari definitely grew on me.
 
Chrome. Couldn't attach to Safari even after 4 years on Mac. Using Firefox for quite a few years before switch to Chrome.
 
Chrome and Safari. Can't tell which I like better after the Safari update.

Is it true that Chrome won't be compatible with iCloud.com?
 
I use Safari 5.1. I was using Chrome for awhile because I really liked the speed, a few extensions, and little convenience features it had, but it used a LOT of %CPU on my MBP. Once Lion stripped the browser of the two-finger swipe, I decided to go back to Safari.
 
Browsers

I use the following in this order:
Chrome > Safari > Firefox

Some websites I frequent are not Webkit friendly, so I have to use Firefox.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.