My personal favorite of the Japanese 0W-20's is the Toyota oil particularly for winter use, it is the lightest oil for typical start-up temp's you can buy.
My second fav' is the Idemitsu 0W-20. If you want a more robust 20wt oil but still with a high VI, that would be my choice
Unfortunately the Idemitsu product is now only commonly available from Subaru (in the US, not sure about Canada), and its not labeled with an API starburst or performance level (SM or SN) so using it in something other than a Subaru opens up warranty concerns.
I know, I was hoping to use it in my Honda. I'm trying to get a PDS out of Subaru or Idemitsu with API info on it, but I'm not holding my breath.