Lots of good places to visit...
Lots of good places to visit and, best of all, i'm told, compared to many other cities on the planet, Perth has very few people and is clean and quiet. A few sights u must get to see though are the beach/seaside/ocean (whatever u want to call it). Again, supposedly some of the most beautiful beaches in the world are to be found in Perth.
King's Park is another 'must see' for those with a few days here. It's a big open space park-land with grassed areas perfect fopr picnicking. You can also find the ANZAC memorial there (for our fallen WWI veterans). You will also find 'the whispering walll' there, a big, long stone wall that u have one person sit at either end of and u whisper to each other. Pretty cool.
The final sight-seeing place i'll mention in here (although there are MANY more) is Rottnest Island. This is a small (well, ok, tiny) island just off the coast (about a 45-minute ferry trip). Great to ride around on your bike, take a leisurely stroll, meet a Quokka (little kangaroo-like marsupial) and of course have a few drinks at the pub.
That's all i'll write about in here, feel free to email me with questions about other 'must see' sights. Again, because i live here, i have way too many fond memories to write about. Definitely playing on the beach as a kid and swimming for hours in the ocean has to be done if you are here in summer. It'll provide you with memories for years to come. Best spot would be Scarborough beach. There is also a shop up the top of the carpark called 'Peter's by the Sea'. They make great fish and chips, hamburgers, kebabs, etc. Perfect to cap off a day at the beach. DON'T FORGET THE SUNSCREEN! Otherwise u will get very burnt, very quickly!!