We really loved Getting Started with Latin, it was simple enough to teach without knowing any Latin myself. The kids enjoyed it and they began seeing the Latin roots in English words. I can give you a few reasons I choose to teach Latin, which may or may not ring true for other families:
practice in logical thinking
learning English roots
higher sciences contain a lot of Latin words
Latin grammar makes English grammar easier to understand
I feel like learning Latin is a good brain workout.
I hope others chime in also. If you want to read arguments for teaching Latin you can search Memoria Press for some past articles on the subject. All of their points may not line up with your philosophy of education, but I find it useful to read what strong supporters say. It helps me make an informed choice for my family.