In addition to Programfilesx86, I would also like to suggest the following as new macros too...

 Code:
function HKLMSoftware32
  $HKLMSoftware32="HKLM\Software" + iif(@onwow64,"\WOW6432Node","")
endfunction

function System32()
  $System32="%systemroot%\" + iif(@onwow64,"syswow64","system32") 
endfunction


It seems like I use these all the time now, when trying to work with older 32bit systems along with the newer 64bit ones.