If you have done prison time for a felony DWI and are subsequently charged with another one, I would say that the chances are pretty good that you would receive another prison sentence, this time much longer than 2 years. As you know, a felony DWI (3rd or more) in the State of Texas carries from 2 to 10 years in state prison. Any felony can be enhanced with a finding that you committed the crime using a deadly weapon, which can bump the charge to a second degree felony with up to 20 years in prison. Many texas district attorneys have started routinely charging folks with a felony DWI with a deadly weapon enhancement (because people were operating a motor vehicle while doing so). Moreover, assuming the deadly weapon enhancement also applied, you could be enhanced again under Texas' Habitual Felony Offender law with a first degree felony (carrying up to 99 years in prison) because you have a prior felony conviction.
The bottom line is you need to stay away from a motor vehicle if you have been drinking AT ALL. Most other people don't have this huge burden hanging above their heads, but you do, and you need to act accordingly. Given this reality, you might even consider giving up alcohol altogether. The risks for you are just too high.
Disclaimer: This answer is provided as a public service and as a general response to a general question, it is not meant, and should not be relied upon as specific legal advice, nor does it create an attorney-client relationship.
Paul makes excellent points. Ask yourself this question--if you received the minimum sentence (two years for a crime with a 2-10 year sentencing range) and then committed the same crime again, what possible incentive would the judge or jury have to be lenient the next time around? The understandable mentality of many judges and juries in that circumstance is that the person is not going to stop drinking and driving unless he is physically prevented from doing so through incarceration. The fact that you're asking this question lends some credibility to that reasoning. As Paul pointed out, it's simply not worth the risk.
Both of the other answers are correct. In addition, if you are to get another felony DWI, the prior felony DWI can be used to enhance your punishment. (It does not matter if they all rely upon the same misdemeanor DWIs so they are essentially being used twice for enhancement.)
Moreover, if you went into prison for 3 DWIs (DUI is driving under the influence and applies to persons under 21), then all 3 convictions count separate. (This is for sex offenses and alcohol offenses only.) It sounds like it is possible you could be facing a minimum of 25 years in prison if you do it again (unless 2 of the offenses you went on last time were misdemeanors.)
I don't care what a cab costs, it is a lot cheaper than a DWI! Sometimes you can beat the rap, but not likely in your situation.