Ants are a real problem. It really helps to know what kind of ant you have. Not all baits and/or poisons work on all types. For those of you that are worried about pesticides, try using diatomaceous earth. It cuts the exoskelaton of insects and other pests. You can get it anywhere there are pool suppliers, garden centers, etc.
To find the best solution for your infestation, you need to use a piece of clear tape to capture a couple ants, take it to someone (not a Home Depot or Lowes) that sells pesticides (we use one that sells to professionals but will sell to the public, they just don't advertise that part a lot). They can tell you what kind of ant you actually have and what the treatment the options are that they would recommend. They will tell you what is safe to use around your animals and children. Where you live makes a big difference in these matters (climate can be a big factor). Then, the decision to go the organic or chemical route is up to you (most carry both kinds of treatments now).
At our house, we use boric acid for some of the little buggers, baits for carpenter ants, diatomaceous earth as a general deterrent. It seems like a never ending story. Our are gets very few freezes and the bugs thrive.