Just thought I'd share my philosophies on rounds to carry and why. This gets asked a lot, so I figured that I'd share some thoughts. If you have some favorites, feel free to share them as well.
I tend to prefer bonded bullets. Some people out there make claims that bonded bullets over-penetrate, and non-bonded bullets do a better job of creating wounds due to fragmentation. Bonded bullets were created for penetration, but they were created to eliminate the problem with fragmentation. Non-bonded bullets will fragment, and not predictably. There's usually jacket separation, which reduced the integrity of the lead core, and then the lead core can either fragment into pieces, or else the core can overly-flatten and deform. All of this can cause under-penetration, and I would rather have a bullet over-penetrate as opposed to under-penetrating. This is especially true if you spend a lot of time in a vehicle and may have to shoot through a door or window, or if you live in areas where people wear more clothing layers due to colder temps.
My preferred loads by caliber:
Hornady TAP 90gr FTX Critical Defense:
This is one of the fastest and highest pressure .380 loads on the market. It is also one of the few that has 200+ft-lbs of muzzle energy. The biggest draw-backs of the smaller "micro calibers" are the lack of penetration and performance from hollowpoint bullets. Clothing can possibly clog a JHP cavity creating poor expansion. When you consider that this is a "carry" round, the likelyhood of shooting through clothing is pretty high. The cavity of a 90gr .380 bullet is pretty small and likely easily clogged. Having the polymer filler allows the round to work correctly and predictably, making this the best option in my book.
Speer GoldDot 115gr +P+:
This stuff is HOT. 1300fps and 432ft-lbs of energy make this thing scream out of a barrel. This is a bonded bullet, and the added performance of the +P+ makes this thing one of the most powerful loads on the market for the 9mm. The added pressure allows this round to work well in medium and shorter barrels, but the maximum benefits come from a full-size pistol.
Hornady 135gr +P FlexTip Critical Duty:
For full-size or mid-size frame guns, this is a fantastic option. It's an advanced design that has modified the Critical Defense FTX bullet to more of a partition-style design using Hornady's InterLock design. The construction makes it very effective at penetrating barriers while still delivering results of soft tissue.
Speer GoldDot 124gr +P ShortBarrel:
For carrying a smaller or subcompact pistol, this ammunition is well-designed. The powder is different, giving a better burn in the short barrel. Also, the hollowpoint cavity is larger for better expansion at lower velocity.
Federal Tactical 180gr HST:
The 180gr is slower than the 165gr and 155gr loads, and has less energy out of the muzzle, but design still allows the 180gr to penetrate into targets better and deeper than the lighter counterparts. The 180gr is proven performer. The very wide hollowpoint opening allows it to work effectively through clothing.
Hornady 175gr FlexTip Critical Duty:
While this round is more designed for the longer barrels, the bullet design still functions out of shorter barrels. Still, for mid-frame and full-size guns, this is a very ideal cartridge with excellent barrier penetration.
Hornady 200gr XTP:
This is just a heavy sledgehammer of a round. Having used this load for deer hunting, I can tell you that it is a seriously devastating round with exceptional performance. This benefits barrier penetration due to the ability of the round to maintain inertia upon impact and continue to carry that energy through into the target. While it may not penetrate as deeply in soft tissue, it will penetrate consistently if it hits bone due to that added mass. I would recommend this round for large frame guns like the Glock 20 w/ 4.6" barrel or a 1911 w/ a 5" barrel. The XTP bullet was one of the first bonded bullets on the market, and it is a very consistent performer.
Hornady 165gr Critical Defense:
165gr loads work about the same as 155gr loads, but have more inertia. This, matched with the FTX bullet makes this round a good carry load for more compact platforms like the Glock 29. The higher velocity will make sure that you get good performance from a compact size pistol. The design gives it excellent performance, but you won't have as much of a possibility of over-penetration.
Hornady 200gr +P TAP FPD/TAP CQ XTP:
The 200gr load is the best of all worlds with the .45ACP. 230gr loads have issues with barrier penetration due to low velocities. They do well against soft tissue, however. The heavier 200gr bullet mixed with the +P power increase make this a good option that allows barrier penetration while still causing exceptional soft tissue damage.
Federal HST 230gr +P:
This is another option for the .45. For people who prefer the heavy 230gr bullet, the HST offers a lot in the way of expansion and penetration ability for a round that is only pushing 950fps. With 230gr loads, I am a big advocate of +P options for the added 100fps of velocity.
As you can see, I tend to prefer the Hornady, Federal and Speer loads. I have used loads from these companies extensively for the past 10 years. I have found their offerings to be very consistent and reliable, with reliable feeding/operation in all of the guns I've owned.