Yeah, you can go all season, but you might want winter snows up there. I've gone through some fairly deep snow (8") with good all seasons on my OG9-3's, but snows were even better when I fell into a set. I usually choose a HP or UHP tire with at least a V speed rating. Higher speed tires will generally have stiffer sidewalls and be better all around IME.
I've had good luck with Michelin A/S 3, 3+, etc as an all around tire. They aren't cheap but they are very round (important with a Saab) and they last. Cost wise it seems to work out about the same in the long run. I've used Conti Extreme DWS in the past but I had the belt/round issues that some report and short life. That was a couple generations ago so it would be worth checking reviews.
If you drop down to the 225 you get some additional selections and lower costs, but you'd have to decide if you want the lower profile. I'd lean to the 235 in general, but 225 is fine. I see they have some Yokohama ADVAN Sport A/S on sale $35 off - that's a nice deal and they rate well.
For pure snows, you might want to drop back to an optional 16" tire and wheel.