Depends what you call a house.
OCONUS (outside continental US), the housing is pretty sweet, with a close proximity to post. Friedberg's officer housing, for example, was right out the back gate. Some were unlucky enough to get housed with the rest of the enlisted, about 20 minutes away in one location and 35 minutes away in another.
CONUS, the housing isn't as nice. Around Benning and Stewart, which are built around a huge swamp, there are large water-bugs that look like giant cockroaches that will frequently inhabit your bathroom and kitchen. There are different areas on post where you might get housed, depending on your luck of the draw. (This also applies to OCONUS) Some areas are more crowded, basically like one-level townhouses but not as nice. In some areas, you get a big yard. Either way, the size of your house is dependent on your rank and the size of your family.
My wife and I drew a two-bedroom, one bath at every post. Hardwood floors in Germany, right behind a nice commissary. I didn't see alot of garages in Germany, however.
I'm not sure if the same applies to officers (but I'm pretty sure it does), but there is frequently a long waiting list to receive military family housing. Some posts are worse than others in that regard. Some people rent small apartments or stay in the on-post hotel for a while, hoping that they get a top spot on the list. All while hoping that they get lucky, as far as housing choice. (Someone must move out before you can move in.)
You can just opt for BAH, after filling the necessary paperwork. You basically go to the S-1 shop (the administration folks) when you get to your unit, or the in-processing folks help you with it. I can't remember. You get different amounts of money depending on your rank and the general off-post cost of housing. I believe the highest BAH was in New York, if I remember correctly. Crazy BAH.
Depends on what you like. There are some nice off-post civilian neighborhoods built around military posts nowadays, but you have to get through the 30 minute wait at the front gate every morning. That is a serious, serious problem. I've sat at the front gate at Ft. Stewart for an hour and a half before, frequently. The bigger the post, the longer the wait. This includes lunch-time. If you're living off-post, you either eat at the chow-hall or hit the PX for Taco-time.
Proximity to schools: hit or miss. If you opt for BAH, you get more control over this, but you're at the mercy of the market.
Fairly good housing market around military posts, though. If you decide to buy a house, you can pretty much guarantee that it will be sold quickly after you leave.
