Try changing your fstab entries to this:

umask mounts them with the opposite of values used by the chmod command

777 - <chmod permissions> = <umask permissions>

You don't really need to understand that, but that should work and allow you to read and execute from the ntfs partitions, but not write. It is not a good idea to write to ntfs from within linux, even though the root account may still allow to do this (the ro option may prevent this, however). It normally damages the filesystem. Newer kernels claim to have limited safe writing to ntfs (you can't change the file size), but I wouldn't recommend it.

That's probably more than you needed to know, but there you go.