I drive a new Chev Cavalier (2.2 liter Ecotec Motor which was introduced in the 2003 model). I live in an area where the temp dips to - 25 degrees celsius on occasion in the winter. I have been trying to decide whether to use regular Pennzoil Multigrade 5W30 motor oil or Valvoline Durablend 5W30 Synthetic Blend. According to specs the Valvoline has a pour point of -38C and the Pennzoil -44C.

Does anybody offer any advice regarding my choice?

The penzoil looks better. They say 75% of engine wear occurs at startup so your startup vis at those temperatures are crucial.
I'd also compare CST @ 0 degrees and see which is pumping better.

Not that there is a big difference, but my pour point was slightly off for the Pennzoil in my original message. Actually, the pour point is
-44F and -42C.

I would use the Mobil Drive Plus Clean Synthetic Blend 5w-30 for newer cars in that engine year round .

It is formulated closely to the Saab 5w-30 Synthetic Blend imported to the USA from the UE . Another fine performing lower cost motor oil that is easily obtained .

From the documentation I have (2003 numbers), if you are going to choose between the two oils you mentioned, I would go with the Valvoline. Results from the Cold Crank Simulator Apparent Visc. (ref ASTM D 5293)
Valvoline Durablend = 5800 @ -30 C
Pennzoil Multigrade = 6600 @ -30 C

The Cold Crank Simulator is a test which measures the speed at which a shaft can be turned within an oil that has been cooled to a certain tempature. The lower the number the better. The number is not the speed of the shaft.

Really don't know much about Penzoil, but the Valvoline Durablend 5w30 looks pretty good. It has a stated (company tech data sheets) flash point that ranks right along with that of 20w50 oils.