I think it would be more advantageous to redo the threading structure of Mirc to make it multithreaded (and possibly dual core aware) than just making it 64 bit. The only real advantage you might get from just making it 64bit would be variables that hold more or something, the real power of modern processors is multicore (which requires (if I'm not wrong) multi threading) And I think it will be a very long time before mirc becomes multithreaded (short of some dlls that claim to add this to mirc).
