I own a 19 and a 34. As far as my personal preference, I would recommend the "long-slide" 34 over the 17. When I lived in Nevada, the 34 was my daily OC pistol for three years. Since moving to New Hampshire, I find myself CC'ing most of the time, and the 19 is the one for that job.
I assume that since you mention the 17 you are not looking for something to CC with, and prefer the "full size" 9mm option. With Glock this leaves your options open for the 17, the 17L, and the 34. The 17L I do not personally recommend, as there are some balance issues (in my opinion). The 34 has no such balance issues because of the way the slide is hollowed out near the barrel, topside. I find it to be extremely accurate at distances greater then fifteen yards. Don't get me wrong, ANY full size 9mm Glock is a good choice. It just comes down to preference.
Best of luck with your shopping.