General satisfaction:
* Happiness
* Fulfillment
* Peace
* Bliss
* Well-being
* Satisfaction
* Gratification
* Pleasure
* Joy
* Serenity
More specific words:
* At ease
* Comfortable
* Satisfied
* Resigned (implies acceptance of one's situation)
* Tranquility
* Equanimity (calmness in the face of difficulty)
Words that suggest a lack of desire for more:
* Sufficiency
* Enough
* Self-sufficiency
* Indifference (can have a negative connotation)
The best word will depend on the context of your writing.