Google Chrome

My first impression is largely positive. The interface is clean and simple. I particularly like the "most visited" thumbnails that appear in new windows and tabs. The address bar's integration with search, favorites, etc. is the slickest I've seen. The way pop-up windows are blocked and optionally displayed is clever.

The architectural underpinnings around security and stability sound cool- though it's too soon to determine how much of a real-world difference they're going to make.

I'm going to try to use Chrome as my primary browser for a few days to get a good feel, but so far, I'm impressed.