No matter what the question, if its about a revolver the answer is Ruger.
.357 mag is a good all-around caliber if you're only going to have one. You should always be able to find ammo for it and it gives you the option to shoot cheaper, lighter recoiling .38 special ammo as well.
Do you want double or single action?
Get a 6-6.5" barrel for better accuracy and velocity than the snub-noses but still short enough to carry.
Just my .02 for what it's worth
Blessed be the Lord my strength which teacheth my hands to war, and my fingers to fight:
My goodness, and my fortress; my high tower, and my deliverer; my shield, and he in whom I trust; who subdueth my people under me. -Psalm 144:1-2 kjv, a Psalm of David