What price range do you want to be in?
Highland Park has some of the lowest tax rates, but then again valuations are probably highest in the area.
Also Copper Canyon, Double Oak, Bartonville, Argyle have lower than average taxes.
You can see a chart of the 2012 tax rates here:
On a $250,000 home the difference in tax rates of 2% vs 2.5% might save you about $1000/year....
If you have any exemptions other than the homestead exemptions, it might be less.
Sometimes you have to be careful with this though....just buying based on the taxes. ...you might loose in appreciation what you gain on taxes...or you might loose on city services or quality of life. While I too would prefer the lowest taxes possible, I think some of the places with higher taxes have better quality of life....not always, but sometimes.