Best browser for HTML5 CSS3 on the middle-long term?

Question

If you had to choose a browser (just one) to be the primarily supported browser for a company jumping into HTML5 (CSS3).. Which one would be your safest bet on the middle-long term?

Chrome, FireFox, Safari, IE?

I'm looking for an objective recommendation based on standards driven/compliant, developer tools, fast & correct feature implementations, memory footprint, etc.

UserBase/MarketShare would not be an issue because it would be on a closed environment in which we control the clients (which are basically big machines with a Web interface).

Thanks!

Answer 1

I would say a webkit based browser. That would be the best balance of speed/stability and HTML5/CSS3 features.

However I believe that Opera has the most implemented features.