Well, I got a little clever and made custom tones for each of my "usual" contacts. And one for a general alert. I put them in biteSMS, which lets you have a specific alert for each individual contact you set.
In my voice, the general alert says, "I have a text." For each contact, my voice says, "I have a text from x."
So when I get a text I know who it is and can choose to answer immediately or wait. With the general text alert, I know it's not as important as if it is one of my specified contacts.
The only time this got strange was in a teacher's dept. meeting, when one of my fellow teachers, from about 8 feet away, texted me with a somewhat derisive comment about how the meeting was going. In a clear voice, my phone announced that I had a text from him. Needless to say, he hasn't done that since. 🙂