Well, I'm going to end up echoing David E here, but I'm going to break it down into a few points.
First, having to make USE of your SHTF preparations is unlikely in and of itself, but the MOST likely time you will be using it is in a mandatory (or voluntary) evacuation of your residence. So basically, get out, get clear of the danger, get to a place where you and your family can stay, and wait for it to be safe to return (or not. Get a new job where you've moved to, etc. whatever, it's up to you at that point).
You're not going to need thousands upon thousands of rounds in that situation, so you can afford to enhance the performance a little. Green tip, hornady red-tip, whatever you feel has enhanced stopping power, penetration, accuracy, whatever. Reloading components and equipment come in handy here because you can manufacture your own ammunition, and then store the COMPLETE ammunition, prepared to go. And you can make it as lethal as your heart desires, optimize it to your rifling twist (I believe 62gr bullets are considered the best bullet weight for a 1:9 twist barrel), etc.
The other situation, and less likely, is the one where you dig in and basically hold what you've got. If you've got two or three full ammo cans (3000 rounds) stocked up, you're at the point where you're likely to run out of food or water before you run out of ammo while dug in. A few orders of canned heat from Georgia Arms (55gr FMJ, brass cased ammo, $350 for 1000rds) will do that.
I'm going recommend reloading for that situation too, but I'm going in kind of the opposite direction from David E in this case. I'd say, train with the factory 55grs, and as you use them up, reload the cases to your preferred SHTF loads and store them.
Without reloading though, it's just a matter of balancing cost vs effectiveness. I'd say a good rule of thumb is, buy as much enhanced-performance factory ammo to fill as many magazines you intend on taking with you if you're bugging out. Get the cheaper FMJ rounds to stock up.