You can look at buying property (im assuming residential property) in a couple of ways.
If I were you, I would look in NE McAllen..more specifically..the Gonzalez Elementary School District. That's going to present you with mostly new construction and no fear of living next to drug dealers. This will help you out also because of the resale value in this area.
I personally live in NE McAllen and know that I bought my property for the correct comparable price per square foot. I know that when I get ready to put a for sale sign on my yard, I'll have a great resale amount on my hands with the appriciation in this area/neighborhood.
Sharyland ISD is also a good location to look at as well. Some claim that it and McAllen ISD are two of the best school districts in the area.
Now this is just a very very short overview, but if you are really needing help, I'd be happy to refer you to someone that can definetly help you out. (I would do it myself, but I deal primarily in commercial real estate down here, not residential) Feel free to PM me if you want. If you need any sort of references...
Texas Real Estate Broker
(1996-present)
CCIM - Certified Commercial Investment Member(2002-present)
Masters - Land Economics & Real Estate
Texas A&M 2005
Greater McAllen Association of Realtors
Director (2006-present)