Great thread, I agree with you Wolfboy Slim, masks add another great dimension to a live show...I see Kiss mentioned, but I think we should draw the line between makeup (especially glam) and masks.
I too, really like, The Mummies and the bandage gimmick cracks me up.
The Mexican wrestling masks worn by, Los Staitjackets and the Dwarves, look brilliant. It must be murder to play in that getup in summer.
The Kings of masked shows around here (Oz) would be T.I.S.M. whose identities have never been revealed behind an unbroken line of diverse and bizarre masks.
However, I'm rather partial to 'Zorro' eye masks, which I think look excellent when worn by 6ts trash bands or Japanese Garage acts like the 5,6,7,8's and the Stompin' RiffRaffs. I think they would be my favourites, (though they're not always masked).