Same problem here too. We have "sugar" ants and have the little raid boxes out. Last year we used the Terro products with some success. This year they seem to disappear while we have the raid boxes out. When I throw them away they're back in the kitchen in about 1 week.
Last year they took over our kid's sandbox too. I hate, hate ants. I'm seriously considering calling an exterminator this year. I just want them gone.