From the most widely respected and well known ant killer comes the TERRO PreFilled Liquid Ant Killer II Baits. All TERRO products are good, but this one has everything else beat. It comes in a prepackaged liquid formula in bait stations, This means you don't have to handle the bait. Just place the station where there is known ant activity, and let it work. The active ingredient is borax, which is a slow kill and allows the ants to take the bait back to the colony. Once there, everyone eats this bounty, including the queen, and the colony is eliminated. Best of all, it is a sweetened liquid, so it is easy for the ants to consume, which makes it highly desirable, and that means they want more of it. TERRO liquid baits are the best, bar none!
When you know where ants are coming in and you want to head them off at the pass, try Combat Ant Killing Gel. This gel comes in a syringe, so you can apply it virtually anywhere that there is a known ant trackway. You can place this gel directly in their path so the ants have to stumble on it, and once they do, they will swarm over it and consume it. The active ingredient is fipronil, which is a nervous system disrupter. It works slowly so that the foraging ants will take the food back to the colony, share it with others and the queen, and the entire colony will die. It is exterior grade, so it is just as effective inside and out.
For quick knockdown with residual effects, Raid Ant and Roach Killer will do the job. From one of the most trusted names in insecticides, this is the standard spray by which all others are judged. The active ingredient is a synthetic pyrethrin made from the chrysanthemum plant. Not only does it kill ants on contact, but the formula is mixed with an oil-like petrochemical. This means that the spray will stay moist and active for up to 10 days, killing all the ants that cross the sprayed path. You'll have to repeat the application, but the spray will keep ants out and away from your dwelling. Although it will not directly kill the colony, it's quick knockdown effect is a valuable weapon if your place is overrun by ants.
For fire ants, you want the most effective killer there is, and that's exactly what Compare-N-Save Fire Ant Killer Granules are. Made with bifenthrin, this is a pyrethrin-based ingredient that effects the nervous system of the ant when they come into contact with it. It's easy to use, just pour it directly on the mound, the fire ants and the queen will become inundated with it, and the colony will die off. Of course, this is a dedicated fire ant control product, so unless you pour it directly onto an ant colony, it won't work on regular house invading ants. But fire ants are common in the southern United States, and this is a sure fire way to rid of them.
For the best and safest ant killer there is, use Safer Brand Diatomaceous Earth Powder. It does not use any chemicals, is safe to use around kids and pets and it is even rated for use in organic gardens. It works because fossilized diatoms are ground up into a powder. To us, it feels like grit, but to an ant that walks over it, or ingests it, it is like being chopped up with razor blades. The ants die from moisture loss, due to the abrasive characteristics of the powder. Sprinkle it on known ant trackways, and although it won't kill the colony, it will eliminate any ants from entering your dwelling. It can be used indoors or out, but it works best in dry places.