Well this is why I've gone back to just buying the DVD/Blu-Ray movies at the store when they're on sale. Got Terminator 2 for $5 on Blu Ray at Target last weekend. I just think that if I buy it on iTunes I should be able to have it DRM-free.
I wondered about PlayStation Store movies too, but as I've heard, those are also bogged down with DRM and will not let you back up to an external hard drive. I could be wrong, but that's what I've heard. I would also imagine that those movies also exceed the 4GB file size limit for FAT32 drives.
I have tried Tunebite in the past, but it just seems really buggy and the resolution comes out horrible just like Aimersoft.