Rather than making a list of my favorite KM blogs, which is always changing, why not make that list available to the public. And instead of a blogroll, why not put it somewhere everyone can use it.
I just created a knowledge management Blogdigger group for this purpose. The nice thing about this particular tool is that you can get a copy of the opml file (the list of blogs), or you can subscribe to the web feed of the entire list. When people add/remove blogs, you will get the changes in that single feed. You are welcome to add your blogs to the list too. (If the list appears empty, it's because Blogdigger is still retrieving content. Within a few hours, there should be content there.)
Other KM blog lists exist, of course. The KM entry in Wikipedia has a list of blogs. Bill Ives maintains the list of KM blogs for BlogBridge. kLog News is a demonstration by Myst Technologies of their aggregation capabilities.