It is NOT a crime to consume alcohol and get behind the wheel of a car in Texas (unless you're a minor). The crime occurs if someone gets behind the wheel after they have lost the normal use of their mental faculties, their physical faculties or if they have an alcohol concentration of .08 or higher.
The easiest way to avoid being caught up in the DWI web is not to drive if you've consumed alcohol - call a cab, catch a ride with friends or give your keys to a designated driver. If you are going to drink and drive, you need to limit your consumption to no more than one drink an hour (the amount of alcohol your body can eliminate in an hour).
BTW, a very interesting posting from Mr. Lawrence Taylor on MADD and their drive to have interlock devices installed on all new cars.