Heh!
I sympathize with the other IT knowledgeable types here, in any of the non-specialist shops I have to try and shut out the sales chatter and bite my tongue. I have failed a couple of times (and was glad I did) but probably the worst was when the Pentium 4 was the latest CPU on the block and the sales droid was trying to sell a new P4 system to a sixty-something woman as a machine for her to check email, browse the web, etc "Oh yes, when you have a lot of emails you'll definitely be glad you have a Pentium 4..." *eye roll*
Needless to say I set her straight and she asked where else she should go to buy a suitable system. :¬)
On the carry front, 'largest comfortable calibre' is the advice I have always heard (right from years and years ago) and I apply it to both concealed and open, even though I am not a fan of concealed carry, actually. For me that's a 10mm Auto and I'm still thinking about what I'll use as a pistol for those occasions I choose to carry concealed but Springfield Armory's range is getting a lot of my attention.
My fiancée is considering several smaller calibre guns but she's almost exclusively interested in target shooting, not self defence carrying. For now, at any rate.