Whether you might actually be seeing hobo spiders depends on where you are (I found no locality info in your profile.) See the distribution map here (click small map to enlarge). Also, as explained on that page, hobo spiders look exactly like maybe 200 harmless relatives to the naked eye. In the city of Seattle, they are almost vanishingly rare compared to their successful competitor the (harmless) giant house spider. As for your wife’s bite – did anyone see that spider? If not, it was probably a misdiagnosis and not a real spider bite.
As already pointed out by Johnny L.A., this one is also debunked on my site, in its original “three feet” form.
Seattle boasts 3 species of Tegenaria (European house spiders) which, like the Three Bears, are small, middle-sized and large. The large one (“giant house spider”) is the most conspicuous because of its size. The ones people actually see are the mature males that wander in search of mates in late summer. They may be totally absent from a few houses but most probably have 25-100 of them in secluded spots. The detailed architecture of the building will determine how many of these end up running across the living room; in some cases the males have little opportunity to reach the human-occupied spaces (probably to the mutual satisfaction of the spiders and humans :)). These spiders don’t know you exist; if you’re scared of them that’s your problem. In reality they are so docile that I use them as hands-on demonstrators for school children.