I've owned 4 different Glocks and 4 different XDs. The G17 is the way to go for a first hand gun.
They just work. You can fix anything that breaks with a minimal investment of time & money into parts, instead of sending it back to the manufacturer. They don't have the grip safety, which is just annoying. Putting a piece of innertube over the grip helps you hold on better, and it keeps that thing depressed. The magazines are almost indestuctable, wheras some of my XD magazines were returned and replaced due to cracks.
However, the final decision is yours. I've owned many, shot man, and enjoyed them all. I just feel the G17 (or 19) is the way to go for a first time pistol owner.