I have two of each in my handgun collection.
.22LR & 9mm in autos (I also just sold a .45)
.38/.357 & .500 in revolver.
I feel that just like anything else, everything has it's place in the world. my .22 is for fun and I just liked the capacity of the auto and I put a red dot on it for fun. My .500 is for fun but also (one of these days) for hunting hogs.
My .38/.357 is for home defense (and fun of course) so I have a choice of a "mild" .38spl, "intermediate" 38+P or "power" .357mag. My 9mm is for fun, inexpensive shooting and also some for home defense. I also put a tactical light on it to aid in the HD.
As for "discussions", the only ones I've really seen on this section is the "big game" hunting threads and the choice in caliber. Should I get a 454, a 500, a 460, a 44 mag, is 357 enough.... But again, it's much more relaxed then the "discussions" on the other forum.