If you don't plan on carrying it all the time, get the 17. I love the 19/23 size for the one-size-fits-all type of gun, but the 17 is the original Glock and for home use and competition use it's going to offer a little more than the 19 will.
It carries easily too, not as easy as a 19 but it's not that big of a difference.
Ooops, seen you got the 19. It's a good choice you won't regret it but a 17 or 34 factory slide won't fit as the 19 size frame uses a smaller size locking block (basically the 17/34 barrel lugs won't fit in the 19). You can buy an aftermarket (lonewolf) long slide that will fit the 19 though, at least I think so.