For the lawn I use Antstop! granules by Home Defence (comes in red canister with a picture of an ant on the front and a black lid). It works well. I had three different ant nests on my lawn and they were gone within a week. Being granules, no dust to breath in. You can also mix with water and drench the ant nest. Safe for pets and children once application has dried.
I also use the Antstop Bait Station (I bit like the Nippon Ant Trap), and find them a lot less messy, and safer than Nippon, as you only have to break off little black tabs, and place in vicinity of ant run. I use the Antstop! Bait Station on my paths.
I dont work for Antstation! Just their products works well.
I appreciate that some people may find the little creatures fascinating, but not in the middle of my lawn. And actually, given that there is now an ant super colony covering most of the globe, I don't think the planet will miss the odd thousand critters that used to invade my lawn!!!
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8127000/8127519.stm