RE: Coveralls vs. Jacket + Bibs...more versatile?
I would definitely go with the bibs/jacket combo. I've been hunting the upper midwest for years and it has always served me well. I wear the Artic Shield H3 combo, and I love it. Lots of layers underneath, too, and mittens instead of gloves. Stock up on hand warmers as well -- that's be $0.99 well spent every time they save your fingers and toes!