I think a general rule of thumb is that you don't count the basement, even if it is finished. At least that's how it is for property tax purposes. And it makes sense to me too, as basement area, even when finished, often isn't as nice as upstairs, because you usually have a lower ceiling (although not so much with newer construction), usually isn't heated as well, often has smaller windows, etc. Still, there are exceptions to any rule.
Anyway, I answered in the 1000-1499 range. It's assessed at 1106 square feet, but could be "fudged" up to around 1455.
Here's how the state determined its square footage:
Original main level: 16x34=544
second level: 16x34/2= 276 (it's classified as 1 1/2 story, so they just divide the main level by two to get that, no matter how big your dormers are)
enclosed front porch: 8x16=128
enclosure on the side that has a bathroom, laundry room, storage: 6x27 = 162
Total of 1106.
However, most of the upstairs is full-height, and the area up under the eaves is where most of the closets are, so being "1 1/2 story" it actually gives up very little room upstairs.
I also have another enclosed porch on the side that's 7x11, which for some reason isn't counted. It's fully enclosed and lockable, and has a electricity, lighting, and a spare fridge out there, as well as storage so it gets used. And it even stays above freezing in the wintertime, despite not having a lick of insulation anywhere!
There's a reason i know the details of my square footage this intimately...it's not like I do this stuff for kicks! Back over the summer I wanted to build a barn with a loft, to use as a garage. It came out to 1200 square feet. I got shot down by the permit office because in my neighborhood no secondary buildings are allowed to be larger than the primary. And this was close, at 1106 versus 1200. I tried to get them to re-evaluate the square footage, but no luck. So I went with a smaller garage that was 24x40 instead of 30x40. Also had to lose the loft because of a height restriction.
If anyone wants to check out the garage, there are some pics of it at
http://photobucket.com/albums/v247/jgandrew/Garage/ , in various stages of construction (and it's still not finished; they just need to pour the slab at this point.) I guess the garage is almost more McMansion than the house!