I like to "test" things, so I use Chromium Canary 98% of the time. It has pages n' pages of experimental features (chrome://flags) to play around with.
The only extensions I *need* (must-haves) are:
1% of the time, I use Opera-Next. Unlike all other browsers, you can make Opera look any_way_you_want. Customization goes way beyond simply skinning it with canned themes. In particular, I like to run my browser tabs on the bottom. All browsers should have this option, IMO!
Have you tried the Opera-Next App (aka Mini Next) on Android, cariboo?!?!?
The only time I use Fx is for critical downloads, e.g. via the DownThemAll! extension.