Buy something that you will carry. For carry, it's my 642 in .38 Special+P or my PPK .380 because they are comfortable as hell and will stop an attack. For home defense, it's my Sig 229 9mm because it happens to live in the Gun Vault next to my bed. For Zombies, it's the 1911 in .45 ACP because I shoot it the best and it transfers more energy. I tend to stay away from these conversations simply because we are dealing mostly with opinions. Is a .45 more powerful than a 9mm? Yes, it is. Is a 9mm ineffective as a defensive/offensive weapon? My opinion is that it will do the job and the ammo is far less expensive leading to more practice, leading to better shot placement. Is a .38 or .380 ineffective? Don't know. I've never shot anything with a heartbeat with those rounds. I'd sure as shit rather have my .38 in my waistband than my .45 in my safe though. To the OP... Glock- I've owned a 17 and a 26. Both very accurate, very reliable, but were not comfortable in my hand. XD- I've owned a compact XD-40... very accurate, very reliable, more comfortable than the Glock, but I didn't like the trigger. PX-4... no experience with it, but I've read good things. M&P... no experience with it, decent reviews. My all-time favorite sub-compact 9mm was my S&W CS-9. I sold mine and they don't make them any longer. Too bad, it was perfect. Flame on with the pecker-measuring, but just carry something. The good-guys need more firepower out there.