Here's an example of a shot I took using the wide-angle adapter on my digital camera. It brings the focal length down to the equivalent of about 24mm. It also introduces vignetting in the corners unfortunately, but often you can get rid of that (as I've done in the second picture). I applied a 5% Pinch filter to get rid of the distortion, and this makes the picture look much more natural. IMHO of course! It still suffers slightly from me tilting the camera up to get the roof in, which gives the perspective of the building "falling over backwards" (converging verticals), but the lines are at least much straighter without those ugly curves.

Then a quick Free Transform in Photoshop and you can see the building looks much more natural. Unfortunately this introduces large missing areas which need to be either recreated or cropped out. I didn't want to crop too much as the sky would have cramped the cottage if I brought the top of the frame down to just above the chimney. So I went a bit mad with the Clone tool just to see what could be done, and the result is the bottom picture - not cropped at all! Just shows how easy digital faking is - the whole cloning process took about 15 minute maximum to fill all three "triangles". Compare with the first image to see how much of an improvement it is...