Garrett,
http://www.wildmind.org/metta/introduction/metta-prayer
This is very close to the words attributed to the Buddha, adapted into prayer form. Consider doing this at the beginning of your meditation, instead of the end. It helps loosen and free the mind, so it develops concentration quickly. Saying it at the end as well is certainly fine, but we can think of it as filling the tank before driving. When I switched to metta before the mindfulness meditation, I noticed a dramatic increase in the stability of my practice.
With warmth,
Matt