These are original size screenshots of some page heading.
I think such bad results may be achieved if Chrome and FireFox rasterize first and scale after that, instead of scaling first and then rasterizing.
To reproduce, here is the code:
<h1 style="font-size: 300%; color: #4f81bd; font-style: italic; font-family: 'Times New Roman', Times, serif;">WINTER ACTION</h1>
Update: Many people reported FireFox and Chrome render fonts OK for them. HN comment and tnm91 suggested that DirectWrite may be disabled, due to outdated video driver. It was true, I updated diver and DirectWrite become enabled, but rendered hadn't changed. Then sulliwan suggested to check CliearType - I enabled it and now FireFox and Chrome render text OK.
Thanks for the help!