Just to stick up for Perth, which always seems to get a bit of hard time on these threads, we've been here for 18 months now, and have loved every bit of it. Yes, it can be expensive, but wages are generally higher. We are considerably better off here financially than we were in the UK, and are enjoying a much higher standard of living. We do work in IT though, and am conscious that this doesn't apply to all fields.
We also do live quite far out, in the dreaded suburbs, but love it. There's loads of beautiful, clean parks, the beach is 5 mins away, we have big shopping centres in joondalup which is all we need. There are 2 cinemas withing a few minutes drive, a massive sports arena also close by, and the train takes 30 minutes into the city. We both commute in, and can count on one hand the number of times train's been delayed. Being near the end of the line, we always get a seat.
I know Perth seems to have a reputation as being boring, but we've not found that at all. Our kids are sports mad though, and most of our weekends revolve around some kind of sporting activity. Much more pleasant watching soccer here though, last Sunday morning was 20+ degrees, beautful sunshine and we're still in winter. In summer they have the open air cinemas at Kings Park, which are fab.
In terms of the heat, I think Perth summer's are more bearable than Sydney, it's not so humid and there's always a nice breeze by the coast. I've certainly not found it too hot to be by the sea yet, though I am a total sun worshipper (hence why we chose Perth in the first place).
If you prefer living more rurally, then I'd suggest you look at some suburbs in the far North of Perth, especially if you're not likely to have to commute into the CBD. There's a lot of housing development, so might be a good option for a joiner anyway. Suburbs like Yanchep, Two rocks are reasonably priced and you'd get quite a lot for your money. You'd probably find similar suburbs South of river, and in land, but I don't know them so well to be able to comment.
If you like I can PM you a breakdown of our income and living expenses to give you a better idea of costs and can give you more info on specific areas / schools etc.
Good luck, was the best thing we've ever done, and we'd never visited Perth before we sold up and moved over. I had to nag the other half for years to make the move, but he was sold within a week of getting here and I'd agree with Koala, I've travelled and lived in many other places, but in my opinion Perth has to be one of the best places for bringing up kids.