i really cant tell the difference between a good screen protector and the regular screen without it, so why not?
having a case is a whole different story. really detracts from the aesthetics of the device. i think i'd rather have insurance than use a case (you can argue that saving money on a case by not getting one would go towards the cost of insurance anyway), at least for a beautiful phone like this one. also the fact that if anything breaks including the screen you have to replace the whole phone anyways. i hate insurance but i kinda see it as mandatory for this phone in particular.
still... even with insurance i think a simple screen protector is worth it. i dont think they will like you trying to replace the phone for a scratch, and i wouldnt want to bother anyways, so why not have it?
for anyone arguing it ruins the visibility or the user experience... maybe you bought really horrible screen protectors in the past as again i really cant tell the difference without looking very closely for the slight seams on the sides past the edge of the lcd