Even though I have this preordered, I am fairly certain it won't be limited. None of the Blizzard CEs have ever really been limited, except for perhaps the original release of WoW. Right after release, scalper hype pushes price up but as soon as they realize there are a billion copies out there, they eventually let them go for cheap, especially when retail stores start clearancing them out. And then we all laugh at their stupidity.
I'm myself debating whether or not I should cancel my amazon CE preorder and just wait. I am not super pumped to play D3 right away, was not totally blown away by the beta, and have a backlog of other games; so maybe I will skip picking this up right away and wait for it to become available cheaper. I got the SC2 CE from BB for $50 about a year after its release.