Responding to other posts, I wonder how many folks don't live near their Netflix shipping center. I live just outside of New Brunswick, NJ, which is where my discs go, and so when I put a disc in the mail, they get it the following day and ship the next one. For example, if I get a movie out with Monday's mail, I'll receive the next movie on Wed. Does everybody live pretty close to a shipping center, or do some live far enough away that it takes two or more days for them to receive a disc?
When I was with Netflix, three to four days was the best they could manage, although I am admittedly in one of the more rural, unappealing areas of the US. Essentially, I would always try to send out all three discs on a Monday in order to receive the new batch Thursday or Friday, watch them over the weekend and get them back in the mail at the beginning of the week. God forbid there was a holiday during the week, though...
More recently, I was with Blockbuster's service and the turnaround was slightly quicker -- when they actually decided to ship me something. Three times I ran into the issue of swapping my discs at the store level and then it would take several days for the service to even register that they'd been checked in, leading to 7-10 days before getting new DVDs. I chalked it up as a fluke the first time (and got several free rental coupons from customer service), an annoyance the second time, and cancelled when it happened yet again.
It looks like I'll be heading back to Netflix now, so we'll see if the distribution times are any different.