As way of continuing we bought a IP out at SMithfield Plains in July 2009 after alot of research up there and see nothing but good things for the area.
The Playford Alive project had been pushed forward and the sales office had been opened. Anyone who has been around the area in last 6 months can see the huge changes taking place out there.
Ours is a 3 bed trust style on large corner block with options for development later on. Obviously were worried as people constantly tell you about the bad tenants but we had a older couple working for the government move in who appreciated the basic reno we had done and have been perfect tenants so far no issues at all! And very happy with our PM from Elders at Munno Para by the way.
As a young couple we found the purchase price and rental yield to be the determining factors as it allows us to make our next purchase sooner. The capital gains that are happening in the area are just the bonus for us (and they are looking good so far!!)
We found the Playford Alive site great in our research (especially the links to the overall and individual suburb masterplans)
http://www.playfordalive.com.au/playfordalive/
Also RPdata was invaluable as alot of property up there have been on the market for awhile, ours originally was asking 210´s and as we saw it had been around for 6 months with price drops and passed in auctions were able to settle for 186.
Hope some of this helps, sorry for the length!
Cheers