There are a few changes in the 40Gb PS3 that may not sit well with gamers. The omission of two USB ports, down from four and the exclusion of any memory slots for different media types are two lesser cuts to the console. The biggest cost cutting technique just may make gamers cry foul however. The 40Gb PS3 will be the first in the lineup to not be backwards compatible with older Playstation and Playstation 2 titles. "Backward compatibility is a nice secondary consideration, but it's far from the number-one priority, said Tretton. This seems like a strange departure since one of their earlier campaigns when they were about to launch was the fact that they were fully backwards compatible.
There are rumors, but no confirmation of a pack-in Blu-ray movie with the 40Gb PS3. That movie being Spiderman 3.
Source:
ARS Technica