I've lived in SD for too long, and in Sioux Falls for about 3 years now.
If I might ask, which industry do you work in? Unless you've got your job lined up beforehand, I would strongly suggest NOT moving here. SF has a very "backwards" and small-town approach to finding and hiring people for professional positions. At least in the IT field.
As for housing, SF as well as the surrounding towns are popping up quite quickly into suburbanite subdivision hellholes. In town there are still a couple nicely developed, varied neighborhoods, but most of the older ones are being overrun by white trash, immigrants, and what have you. There are some parts of town you don't want to visit after dark (well, it's not such a problem for some of us :P, but you get the idea).
Depending on how far you'd want to drive, there are several smaller towns come-subdivision that are popping up and growing. You can get some pretty inexpensive houses in Tea or Beresford, for instance (and in those general areas). They're like 20 minutes south. Brandon is about 10 minutes to the N and also growing. You'll drastically cut your daily commute if you both work and live near the SW side of town (which is the case for most people).
There's still a lot of farmland within 20 miles within SF. It's not all that difficult to find abandoned farmhouses fairly close (within the glow of the city lights), on back dirt roads. I guess it depends on how much land you want. Personally, I don't find SD land to be all that savory as an ownership proposition, except for maybe a shooting range. I'm an Northeastern boy at heart (grew up there), even if I hate the crowds. Still, living in town isn't pleasant, either. :P
If you do buy land out of town, plant many, many trees all over the property. It'll hide the eyesore that is the praire and shelter the house from prying eyes and the driving winds.