Too many people are making a costly mistake when canceling their Netflix subscriptions, and since there may be many Netflix membership cancellations between now and September, this is a very important special reminder to help save you from a nasty surprise after canceling your Netflix membership. If you read only one thing on this site between now and September, read this:
Absolutely, clear your Netflix queue of all DVDs and make sure all of your Netflix DVD returns have been acknowledged by Netflix before closing your Netflix account. If you do not take this precaution, Netflix may charge you for DVDs they claim are "missing."
Numerous former Netflix members have reported that Netflix charged their credit cards for missing DVDs after they properly closed their accounts and returned all of Netflix's DVDs. Unfortunately, Netflix is always in control of any evidence when this happens, so there is no way to prove the fraud.
Once you close that Netflix account, barring signature confirmation, you have no way to prove Netflix received all of the DVDs you returned to them. Netflix may claim you did not return your DVDs, and they may stick you with a charge of $20, $40, $60, etc. on your credit card. If Netflix does this to you, you may have little recourse. You will have to dispute the charge with your credit card company. If your credit card company does not side with you, you will be responsible for the additional charges from Netflix.
So, clear your Netflix queue, and return all of the DVDs well before your cancellation date. If all DVDs have not cleared your account, report them as missing before closing your account. If you really want to be safe, you might consider sending your DVDs back with signature confirmation. Yes, signature confirmation is a pain, but so is paying for DVDs you already returned. If you can produce proof of delivery, you will have a much better case if you need to dispute Netflix's charges with your credit card company.