Inspect the siding. You don't want water penetrating siding. Its purpose is to shed water, but it's not waterproof. Make sure it is not full of holes and not open on the corners. Caulking around windows and doors is very important - the biggest problem in Oregon is moisture.
Metal flashing on chimneys and above windows can redirect that potentially destructive water too.
Pay attention to stains. A waterline on the gypsum wallboard in the basement is a pretty obvious clue , but there are other more subtle signs to look for. Every stain inside the house should be investigated - it may be announcing a hidden problem. You need to find out whether the toilet is still leaking and rotting out the floor, or whether it's been discovered and fixed, for example. Wallpaper stains can telegraph signs of leaks around wooden window sills.