So the issue I described yesterday does not seem to hit all platforms. But it's still painful to me on my Mac so, as usual, I spent a few minutes hacking a Firefox add-on. It adds a new menu item to the File menu to print "as on screen" and it does exactly what it says.

It's a 0.9 but I tested on a dozen of web sites having very specific @media print styles and it works as expected. Auto-update is not enabled yet, I'll enable it for 1.0. Enjoy!