I've got Furutech rhodium fuses in most of my plugs. These are even more expensive - GBP30 each, from AudioCandy.

Got to be honest - not sure at all. If there is *any* difference, i'd actually say it is detrimental. In my opinion, upmarket fuses, like many tweaks, are less effective the more thoroughbred your equipment is to begin with. If you've got decent equipment, proceed with caution here.