I use Stack Overflow, Super User and Server Fault every day, so I have them pinned to my Windows 7 taskbar with Prism, a web app that lets you use websites like they're normal Windows applications. It's like the "application shortcut" feature in Chrome but with more customisation options.
The default icons (the sites'
favicons) are very low quality when used in the taskbar, though Server Fault's looks okay because of the logo's design. I have been able to find high quality icons for Gmail, Remember The Milk and other sites I use through Prism. Are there high-quality (i.e. larger dimension-wise)
.ICO files available for SO and SU with the logo and no text?
Gmail icon example (I used the
.ICO in the packaged download): From deviant art