I have been watching this thread since it's inception. I find so, so typical that so many posters just can't wait to veer off the main topic and start touting their own non Glock favorites.
I have some experience with Glocks dating back to the early 90's and I currently have several G17's from an early Gen1 up to a Gen3 and a new factory P80 clone. I also have had a Gen3 G19 for many years and a recent addition G48 with Shield Arms magazines. here are my thoughts on the matter:
Since the OP said it was primarily going to be used as a home defense gun, then it's a no-brainer, get the 17. Since size isn't going to be an issue the G17 would be great for a HD weapon. I love my G17's and mine from the oldest to the newest have been absolutely 100% reliable.
OTH, if the Op thinks that somewhere down the road he may want to use it as a carry gun, then the G19 would better suited for the job. Not because the barrel is shorter, but rather because the grip is a bit shorter and that is the hardest part of a handgun to conceal. I find no practical difference in accuracy potential between a G17 or G19. I have heard that using G17 mags in a G19 without the sleeve adaptor may lead to feeding issues as the mag can move around. Because of that I have a half dozen G17 mags that have the Glock sleeve installed and I personally have had zero issues when using them in my G19.
As for the G48, guys, the OP didn't mention a thing about wanting one, just whether he should get a G17 or G19. However, I will mention that the G48 with the Shield Arms 15 round magazine is hands down my favorite carry gun. And if the OP was interested in a carry gun that would be my recommendation.