I have a 1 tera external usb disk whit all my movies.
From a PI point of view is there any difference in performance, stability, filesystem integrity if I choose different filesystems for it?
FAT32 has a 4GB single file limit size and no journaling, ext2 is fast but also has no journaling, NTFS has journaling but is the slowest of the bunch...I would use ext3 or ext4
A lot will depend on how you intend to access it. If only via the RPi then ext3 or ext4 as f1vefour suggested. If however, you want to access it from a Windoze box then you'd be better off with NTFS (You can get readers for Windoze that will R/W ext3/4 but it's another layer to go wrong).
It's not as if there will be any great I/O on it, unless your transferring new files to it.
NTFS is CPU intensive on the Pi but is the best option if you plan on plugging into a Windows machine.