To chime in, yeah, Portland itself is pretty nutty as far as being liberal. Which makes Multnomah County pretty liberal. However, Clackamas county, directly to the SE, tends to be much more sane. Especially as you move farther out into rural portions of the county. Also, your wife being an RN should have NO trouble finding a job here in the Portland Metro area. In the Portland area alone, there are 14 hospitals, not counting the two across the river in Vancouver, WA. There are also countless clinics, nursing homes, etc. All of which need RN's (you didn't specify what type of work she does as an RN, so I kinda gave you the gamut). Also, for her sister, I can't imagine her having much difficulty finding a job here. There are several architectural firms in the Portland Metro area.
A few people have tried to ban pitbulls, but it's never really taken off. GSD's are not specifically banned by any local or county ordinances that I'm aware of anywhere in the state. Some HOA's however do have rules re: the breed/size of animals, so before buying a house, look into the rules for the HOA that it might be in (very few homes are actually in an HOA, so not too much of a worry there....
If you were to move out here, I would strongly recommend Clackamas county over Multnomah. Still close enough to get to and from work in a reasonable amount of time, but property taxes are, in general, lower, and they don't seem to have quite the same leftist mentality that Multnomah County does.