Didn't Pentadactyl stop working a while ago? For a while I was trying to keep it working, making the necessary changes on every firefox update, but eventually it got too much for me and I switched over to VimFX. At first I didn't think it would be satisfactory, but it actually is a quite good 80% solution. What seemed to be a weakness - the fact that it doesn't aggressively change how the browser works - now seems like a good design decision, making it considerably more robust than Pentadactyl/Vimperator in the face of the changes Mozilla is making, even at the cost of some of Pentadactyl/Vimperator's more advanced functionality.