If you're going to keep the icon but replace them all with a standard icon, my vote is to keep them... and include even more icons, all the suitable ones from the standard emoticons (including the ones visible after pressing the [more] button, the R.I.P icon could be cute when making threads about symantec-purchased software).
One of the main problems with the thread icons is that there's too few to choose from. Or perhaps that the ones present aren't always fitting. Perhaps coming up with a set of icons that would make sense for donationcoder.com could be an idea.
Anyway, if you're going to lose the icons, lose the column entirely, otherwise it's kinda pointless imho.