The film that comes with Bodyguardz, BSE, etc. are nothing like Crystal film. Those films are very "rubbery" which makes them great for the body of the iPhone, as they improve grip. But on the screen? Not so great, as the stickiness makes the iPhone harder to use IMO.
Crystal film is not rubbery, and IMO actually improves the "feel" of the screen. Morover, it's thicker than the stuff used on the body. Has already protected my screen in a nasty fall on to jagged rocks--face down. The film was destroyed, and I really didn't see how the screen could have survived without--at the least--scratches or chips. But when I peeled the film off the screen was perfect. I'm not sure I would have been as fortunate had my screen been protected by that think stuff used for full body skins.
I use a BSE for the body, Crystal film for the screen, and an Incase rubber sleeve for the whole thing (the BSE prevents the sleeve from scratching the iPhone).
I think you have a good on using the BSE, Crystal film, and incase. Iam going to order them today. I think the phone will be protected very good