There's a lot of hype regarding the Ruger LCP and other tiny weapons designed for deep concealment. This is nothing new, of course: the pocket .25 was once an extremely popular choice for the same purpose. The .380 is a round that is better suited to defense than the .25, but it is still a concession.
Yeah, the LCPs and the Kel-Tecs fit into a shirt pocket without really showing, which makes them appeal to people who want a deep concealment pistol. They seem ideal to many of these folks, who often think that the smallest pistol they can get will be the best choice for a carry gun.
But why do you want a pistol this small? They're uncomfortable to even hold. Firing them must be even less comfortable. They're less accurate than slightly larger pistols, and most .380s are pretty finicky. Since you likely won't practice much with your pocket gun (due to the discomfort), that makes the accuracy issues even worse.
Some people say they just can't conceal a bigger pistol. It's not hard. Here are some quick tips to get you started:
1. Buy a gun you will shoot, then worry about concealment. You can conceal just about anything. I have a medium build, but I carry an XD45 with shorts, a T-shirt, and an inside-the-waistband holster and it conceals very well. I find it hard to believe most people couldn't conceal at least a smallish 9mm.
2. Know your body. If you hang over the sides of your jeans, you should probably get new jeans. If that's not the reason for it, then you should note that an IWB holster under that overhang is going to be very uncomfortable and visible. If that's the case, don't find a smaller gun to carry that way--find a new way to carry a gun you're comfortable with. Small-of-back, belt, or shoulder holster are all viable options depending on what you plan to wear.
3. Know your wardrobe. If you wear a business suit all the time, your options are different from those of someone who wears jeans and a T-shirt. Depending on the type of carry you find most comfortable, you may want to change your wardrobe. Don't forget, though, that you'll have to stick with the changed wardrobe. As such, if you choose jackets, you'll probably want to switch to an unbuttoned, untucked shirt for summer, since you really won't appreciate a jacket.
4. Buy a decent holster. I don't know how many people have told me that they were getting a smaller gun because their current one wasn't concealing well, only to admit that they had about a $5 holster. Personally, I like Crossbreed for IWB, but you may have a different opinion. A cheapo Uncle Mike's or some such is great for deciding on cant angles, but you'll need to invest a little bit more to get a quality holster. You need one that won't move around too much, holds the pistol close to the body, and keeps it right where you want it. A great way to find holster is gun shows--you can get great deals on holsters others didn't care for, and you can actually handle them, unlike the online deals.
5. There are alternatives. If you just can't seem to get your gun to conceal comfortably, there are options that may conceal well and be comfortable. Purses, backpacks, fannypacks, vests, and the Utili-Kilt are all available with holster options because of people for whom traditional carry options aren't going to work that well. Smart Carry markets an inside-the-pants holster that keeps the gun in front, minimizing grip protrusion. If you don't find a solution right away, ask around. Somebody's bound to have had a similar problem.
If you really can't hide your gun, one has to wonder what the problem is. Maybe the choice of a 7.5" .500 S&W wasn't the best call. Maybe that Desert Eagle was a poor decision. Maybe you should let go of the notion that you have to find an option for pocket carry of a 5" 1911. Whatever the case, try to figure out the root of the problem. If you do determine that you need a smaller gun, don't go to the smallest you can find--get something you'll actually practice with, figure out how to conceal it, and be happy with your choice.