I would get a Glock in 9mm. 9mm ammo is less expensive.
As far as if you should get a 17, 19, or 26, that is purely up to you.
If you never intend to carry the firearm, the G17 would be the better choice. IMO the G19 is not that much smaller than a G17, and the G17 has a larger capacity. You can use G17 mags in a G19.
The G26 would be a better option for both CCW and home defense. The G17 mags will fit into a G26 as well, they will just stick way out.