I bought my first Glock yesterday. Glock 17, factory night sights.
I caught the Glock bug mostly for professional reasons. As a LEFI and armorer, I really need to know the Glock system. 9mm practice ammo is cheap, and modern defensive ammo renders the Great Caliber Controversy moot. The G17 seems the best, all-around choice for teaching, practice and self-defense.
The armorer in me really appreciates the simplicity of the Glock mechanism. Unfortunately, off-white contact paper applied to the grip area seems as close as one can get to ivory stocks for the Glocks.
I tried the 10mm Glock 20 and really liked it. I'm glad to see the 10mm Auto round making a comeback (Glock never abandoned it). That may be my next purchase. Hey, CA law says "one gun a month." Who am I to argue?