The more hardcore DVD buyers (Rob and Matt) probably already know this, but deepdiscountdvd's sale is currently ongoing. Previous years it was only 20%, this time it's 25% off (with free shipping). I placed an order on Saturday for the Batman: The complete Animated series (just over $54), Mask of the Phantasm and a few Godzilla movies. Unfortunately, the animated Batman ones are out of stock, but the sale price will still apply once they restock, whenever that may be.
The sales lasts until November 23rd, so I'm going to place another order for movies that come out in the next few weeks - Kung Fu Panda, Hellboy 2 and Wall-E - that I want to pick up.
DVDTALK and USATODAY work for codes and I'm sure they're a bunch of others also.