Orcades,
I've been investing in the area for the last couple of years. Prices have increased substantially from 5yrs ago, but I still believe there is plenty of growth left.
Depending on what suits your needs, you can either buy brand new houses (or near new) in the developments you spoke of, mor you can buy the older houses in the area.
I have bought 2 new properties in neighbouring Davoren Park, and Smithfield Plains, which have both already shown good capital appreciation for me in only a short time which has given me more leverage into my latest investment, which is an older property.
Even the house and land packages available by builders have increased substantially in the last year or so. They were starting at $165,000+, now you'd be hard pushed to find them below about $190,000
If you were looking to buy old, I STRONGLY agree with Prakman - don't buy just one half of a semi. Leaves too many factors of external influence you have no control over (unless you can buy both sides).
If you are looking at the southern Elizabeth suburbs (there are about 8+ "Elizabeth's") you will pay more because it is closer to the Adelaide CBD. Check out Whereis.com.au to get a better idea of the different suburbs.
I personally have decided to buy a property (this month) in Elizabeth North - the furtherst North suburb of the Elizabeth's. My reasoning is that it is only an extra 1-2km from the rest, but I have managed to buy a stand alone house on an 805m2 block for $139k. There are a lot more semi's than there are stand alone's so it's not as easy to get them, but I believe they are worth the premium. Development has also recently started in Elizabeth North with about a dozen or so new houses now built in different pockets, so I believe the house prices have some catching up to do.
Basically, if you can get a property for about $140k or less (or even up to $150k in my opinion) - I believe you will only basically be paying land value, as the new estates in the area are offering 400m2 blocks for $80k+ now (granted they have nicer surroundings as they are totally new, but you get my drift). Then if it is stand alone, you can rent it out as long as you want, and develop it when ever it suits you, and not being subject to the other half of a semi if you bought that way).
The semi's conversley (in Elizabeth North) go for $125k to as high as $135k for blocks of about 700-750m2. So you have less land, and are attached as well. If you look at the suburbs further south, you can probably slap on an extra $5-10k for the semi's.
You could also look at Smithfield and Davoren Park. But if looking at Davoren park, I would strongly suggest to stay away from the Western side. I looked at a property there recently, and the neighbourhood was scary (even for me, who has driven around these suburbs countless times looking at properties). My reasoning for not buying on the Western side is that all the new developments etc (for now) are further to the East, and North. Absolutely no houses have been knocked over for development in this area, and the way the area looks, it could be at least another 5yrs before that area develops as it is really scungy! (Don't let me talk you out of that, other people may have made really good buys there, I just know that for me, I did'nt feel comfortable looking at that side).
Steve