That's right. It's only ie6 that struggles to resize px fonts. There's nothing wrong with using pixels for font-size these days.
You're list isn't too bad, I would put these at the top of the list as the most obvious ways to tell a modern site.
The site is built in a way so that it loads quickly, lean HTML, Minified & compressed assets.
The site works well with mobile devices (responsive CSS)
CSS3 is used in preference to images
Use of appropriate libraries to simplify the code.