While I agree that AWA is no big deal in terms of overall score, I must say that it's still a good idea to invest several hours in it. AWA are the first section you have on real test, and if you totally screw up - you may get nervous and bomb the whole test. So my advice is - write several AWA essays, just to get used to timing and essay format. Don't agonize over quality, it doesn't matter much, but do some training to feel prepared on G-day.
I was going to skip AWA preparation at all, but during GMATpreps I saw that AWA's giving me a headache, so I decided to write several more essays. I'm very happy with this decision, as on G-day I was very calm and concentrated, and AWA didn't freak me out at all.