my bookmarks either have a blank page, or their proper icon ... I've never noticed incorrect favicons in the actual bookmarks list, ff-win 1.5.0.1
however, I do have an explorer address toolbar as part of my taskbar, and it occasionally goes and gives sites random favicons ... not just from other websites, but from windows apps too... for a while, all my history items showed up with the HL2 icon.
for this site, I just see the blank sheet of paper with a dog eared corner.