Yep, it would depend on what kind of case you have. I know there is a big thread about extended batteries and cases that fit them but I suppose we will just have to wait until we can actually get our hands on one and see what works. I was planning on buying a new case anyway but I think I will wait and get both at the same time.
i current have the amzer dual hybrid case with kickstand and i love the case would not want to loose the case to get a lil more battery life. After doing all the cleanups on the phone i am getting abt 18+ hours out of a single charge.