It is an Intel LGA 1155 (Socket H2) motherboard which is a socket that supports Sandy Bridge and Ivy Bridge processors. Any LGA 1155 CPU is compatible.
Since you are not looking for high-performance I would look at any of the 2nd generation Intel Core i3 family of processors. If you want low power the Core i3-2100T is a 35W Max TDP CPU but it is more expensive than its 21xx siblings.
