Recent Android versions include the ability to disable built-in applications. I've got an S3, and I've successfully disabled all of the bundled stuff I don't want as well as most of TouchWiz. There are some Samsung services I can't disable, but they're bits that are non-UI or are hot-swapable and that would break the phone if disabled but not replaced. The stock keyboard and the TouchWiz launcher fall into this category, neither of which I see unless I go out of my way to re-enable them.
My phone didn't come with Facebook installed, although it did have a link in the accounts section to install the application.
If you really care, root your phone and then you can get rid of anything with Titanium Backup. Or you can do what I do and just install CyanogenMod on it. (Both are admittedly too much effort for the general public but not much for many people here.)
My phone didn't come with Facebook installed, although it did have a link in the accounts section to install the application.