Where on Whidbey? See below for a basic breakdown of the three main areas. Above all, be sure that you're ready to live on an island. Tourist season means long ferry waits, missing the last ferry means sleeping in a the ferry terminal parking lot. If you have an emergency, the ambulance gets priority boarding on the ferry. However, if your pet has an emergency that requires off island care, you will not get priority boarding. Island living is like small town living - some like it, some hate it. It's a beautiful place to live - beaches, forests, parks, etc.
South (Clinton, Langley, Freeland) = artsy, politically liberal, locally owned stores, very white and wealthy, but there are a fair number of folks finding creative way to piece together enough income to live there, ferry needed unless you have a private airplane/boat or can drive all the way to the north end of the island to cross the bridge
Central (Greenbank, Coupeville) = a bit of a cultural bridge between the north and south, has the island's hospital
North (Oak Harbor) = home of the Naval Air Station, more ethnically and economically diverse, less liberal, more chain stores and fast food places, bridge to the mainland