That's the magic formula we use at work (200+ sites, many with 1 million+ unique visitors per month). I apply the same techniques to my own projects, even though it's unnecessary at this point.
Our sites run on a standard LAMP stack (load balanced across between 2 and 25 machines using an F5), memcached for object and query caching, caching at the application level, varnish and nginx for file caching, and limelight CDN for serving images, css, and javascript.
Our sites run on a standard LAMP stack (load balanced across between 2 and 25 machines using an F5), memcached for object and query caching, caching at the application level, varnish and nginx for file caching, and limelight CDN for serving images, css, and javascript.