A smaller gun is better able to fill both roles. A larger guns is less likely to make it out of the house when just going out for a few minutes or what not.
I am one of those people who spends more than I should on getting just one more. When I had fewer like you I was a better shot. I don't personally like Glocks so I have a hard time recomending them.
My top three choices would be, in slight order of preference:
SP101 either 2 1/4" or the 3 1/16". I have both and prefer the longer barrell. It is cheaper and much easier to develop good habits with the .38 and also is adequate for self defense. The extra power of the .357 is there if the desire or need and ability warrants it. One other advantage for a revolver is an inherent simplicty of the manual of arms. Plus they don't wear out, springs don't go bad etc. This is an advantage for someone who might buy a gun for self defense but rarely take it out and practice. This is not recommended but since it does happen should at least be considered in the thought process.
Sig P239 in 9mm. This is my next purchase. The 9mm is cheap to practice with and still effective for self defense. Starting off with larger calibers is often a mistake because bad habbits form quick. It is much better to be a good shot with a smaller round then an ok shot with a larger one. Only hits count but misses can be a liability.
Kahr K9 or if prefered one of the polymer or compact versions. I would stick with the all steel because I prefer the heft and it makes for faster follow up shot. With a good holster or means of carry the extra weight has never bothered me. I have the K40 for myself.
Make sure you have them always store a bit of extra ammo, have extra magazines and a good light.
One of the best things a gun owner can do is help others help themselves with making a good decision when it comes to such an important issue as purchasing their first firearm.
P.S. Never overlook the fun and usefullness of a good .22 but that is another thread.
