I use Firefox and Chrome.
I've definately found some extensions on Firefox that i couldnt be bothered to find on Chrome. That doesnt mean its not there though. I also prefer Firefox look and feel...and customisation options.
I use chrome for the awesome bookmarks folders :), sign in capabilities which automatically sync up with any PC you on, this is great for portability.
Personally though i found Firefox to be more smoother and perform better which ultimately makes that my browser of choice. Chrome also tends to use up HUGE amounts of disk space after a while and i hate that.