it sure is fun to buy different pistols,isn't it? but if i may suggest a different approach,how about buying one that you already have.
assuming that you carry and excluding for a moment a possible home intruder,more than likely the one that you would defend yourself with and the one that could possibly save your life would be the one you carry.it would also be the one that you more than likely practice more with since you carry it.
of the ones you have,the most logical for carry is the g19 because a)it's the lightest b)more rounds than the second lightest.although,a p7 would make a good carry piece also.
if you do carry the g19,my suggestion is,why don't you buy a second one.there are several good reasons for having at least two of EXACTLY the same gun.here are several from the top of my head(no,it's not pointy).
#1-if you have to use it in self defense,the police more than likely will still take your weapon as evidence.if your innocent you will get it back but that may or may not take a very long time.what are you going to do in the mean time for carry?use a different platform that's not as efficient for you?different trigger and POI etc.,ect? if it does take a very long time,it may come back to you rusty and maybe even with a problem...you just never know.
#2-gun breaks,for what ever reason,you ship it off to get it fixed.what do you do while it's getting fixed?use a different one?
#3-what if the s@#t was to actually HTF?where exacty are you going to get parts in that senario or service if something breaks or is not functioning right?if you had at least two you can use the second one or use it for parts.
there are other reasons aswell but these are enough.
if you had atleast a second one,all of the problems could be solved.i know it's fun to keep buying different pistols,i use to do it myself but now i think in multiples(atleast the main ones).
....just a thought.