RE: Favorite caliber and why
22 LR for a mulitple reasons.
But since you mentioned deer hunting I'd go with the .308. The 30-06 would be second. I'm just old fashioned in my caliber choices and like the availabililty of ammo, loading components, etc. I also find the .308 and 30-06 to be accurate, flexible and hard hitting enough for anything I'll probably ever hunt.