Considering the Editorial esteem, reach, indexing, subscription base and quality...the ranking goes in the following order.
1) Journal of knowledge management (emerald) : http://www.emeraldinsight.com/info/journals/jkm/jkm.htm
2) Knowledge Management Research and Practice (Palgrave) http://www.palgrave-journals.com/kmrp/
3) Knowledge and process management (Wiley)
http://www3.interscience.wiley.com/cgi-bin/jhome/6242
4) Journal of Information and knowledge management http://www.worldscinet.com/jikm/mkt/editorial.shtml
5) International journal of knowledge management (Idea Group)
http://www.idea-group.com/journals/details.asp?id=4288
6) Electronic Journal of Knowledge Management http://www.ejkm.com/editorial-board.htm