What's the best engine oil to use? Up North keep in mind?

You'll find as many opinions as there are bellybuttons. One thing for sure: Use full synthetic only. Brand should not matter as long as it is a trusted company, BUT IT MUST MEET OR EXCEED THE CORRECT AFI SPECIFICATION. Look in the manual for that along with the viscosity recommendation for your climate. I don't think you can go wrong with 0W-30/40 or 5W-30/40. IMHO.

Mobil 1 0w-40

I always use whatever the manual recommends. No reason to change from that.

I personally use 20-50 in my Charger, its the recommended oil for customers that complain about the "hemi tick". So that's what I will probably run during the warmer months and switch to something thinner in the fall/winter.
As for brand, I use Mobil1. Royal Purple, Amsoil are other popular brands as well.