Mt Lawley is a very good suburb, with a lot of history and character houses, close to the city and cafe strips. Even if you can't afford to live in the really good ones they set the tone. Depends where you live and if you are living in a flat or a house. Some 'cheaper' flats might have tenants that are not representative of the professionals living in other streets.
If you are looking for character and value for money and don't have to be on the doorstep of the CBD then places like Medina to the south are a good fit with excellent links big blocks and low cost currently if you do however have to be close to CBD or have a post code snobbery then much higher $ will be required