I own a Walther PPQ, and I love it. Despite the fact that it is my absolute favorite handgun, it wouldn't be my pick for this.
Even living in Oregon, I don't see the PPQ as a practical ccw weapon, 365 days/year. Sure, I could pull it off 3/4 of the year, but for 3 months, it's just not going to work.
If I were to pick *one* gun for ccw, nightstand, WROL, etc, it would be one of these:
S&W M&P9c. Decent capacity, great reputation for reliability, and apparently shoots very well.
SA XDm 3.8" 9mm compact, or Ruger SR9c, for the same reasons. These two guns come with full sized spare mags, and grip extensions. If Serious Situations Arise, you can turn that ccw weapon into a duty weapon in less than 2 seconds.
Thankfully, I am *not* limited to one gun. I have my PPQ for range, nightstand, and emergency (WROL, etc) duty, and possibly seasonal ccw. I'll be picking up a subcompact for EDC-- possibly a Ruger LC9.