I have lived in Lynwood, Ferndale, Riverton, Bullcreek, Leeming, Rossmoyne and Willetton. In scale of niceness it goes:
Rossmoyne/Bullcreek
Shelley
Riverton,
Willeton (some surprisingly affordable spots)
Ferndale
Lynwood
Langford (Balga equivalent)
There are nice pockets in each...