I live in Allandale, which is an excellent community type area in my opinion...I do not have children here as they are grown, but there are very good schools near by, can do all shopping within a few miles as it is very centrally located. Taxes are high in Austin, so I cannot compare COL with Round Rock or Pflugerville, both of these are supposed to have great school areas, but I do not know specifics of home costs which vary everywhere. I live in an older area, which is middle class a little on upper side, and houses average $200-$250,ooo, so I think you would like it. We are near several larger shopping malls, and between I Mopac and I 35, The Domain, Highland Mall and Northcross Mall. It is like a small town suburb here to me, with the City, the University and several hospitals within ten miles of home...so look it over...you will like this area...of TX.
If you are looking for good schools, I would recommend Round Rock over Pflugerville. Pflugerville teachers, in general, are wonderful, it s the student population at some of the schools that would make me wary of the district. Cedar Park is a growing community in the same area, and its schools are good too. If you want excellent schools, look in the Eanes district, which is in west Austin, but the area is beautiful and has a reputation for excellence in education. It sounds like you are looking more north of the city, so you may want to check out Leander and Georgetown as well. Good luck!
Aside from Round Rock, and Pflugerville, you could look at Cedar Park and Leander (both Northwest off of 183). If you are going to be working in South Austin, you could try Buda or Kyle.
so youre looking up north? in the south id reccommend Shady Hollow or Circle C.