I use chrome, Firefox is just far slower on my computer.
Chrome, and to actually provide a proper reason rather than "it looks better": it's because it stores all of my settings, history, sessions etc. on the cloud, and considering I store a lot of information on my Google account, the seamless integration in Chrome saves me a lot of time and effort trying to manage it all.
It has kind of become a case of embrace the cloud or fall behind I guess.
I'm a chrome guy but there are some things that only seem to work on Firefox without issue (certain remote access applications come to mind)
Firefox -- because it's never failed me. Had no reason to switch to Chrome on release.

