Congrats on the G17! I own a G26 and CC it in a crossbreed horsehide supertuck and love it. I would keep it stock with the exception of putting some tritium night sights on. Trijicon and Meprolight tritium sights are both good. I bought a Remington gun cleaning kit with Rem clean and Rem oil and that works fine. If you don't own a plastic cleaning brush, pick onE of those up. Other than that, a couple spare mags and lots of ammo and you are good to go 
Glocks are awesome. Simple, reliable, and bulletproof. When cleaning and maintaining a Glock--- a little bit of oil goes a long way....
Enjoy!
-Ryan
-Digicamo PM2, Dragonfly 2 FRN, Assist, Endura FRN ATS-55 SE, Endura SS aus-6 PE, Persistence(Wife's)
-Wicked Edge