Haughtney, a little more info on what type of surroundings you prefer (city central, suburban, or semi-rural) would assist.
Trip Advisor has a modest list with feedback - the one in East Perth (Casa La Rosa) is well-recommended, is very central and has easy access from the airport.
There's also an excellent Italian restaurant at the nearby Baileys Hotel/Motel. This restaurant is open to the public for lunch and dinner.
If you prefer a coastal position, I can recommend a couple in Fremantle that are very good, and cheaper than Perth.
Accommodation is very tight in Perth - hotel occupancy rates are regularly over 80%, which is a dream for most hotel owners.
Perth Bed and Breakfast: Reviews of 14 B&Bs ? TripAdvisor