Re:
It depends on how far you want to go. I've used carbon/leather style protection which can look great and works well for stone chips and cable rub. It can look crawl if it covers decals but good for contoured areas. Heli tape is good if you want to cover large areas but not mess with the clean look of your frame/decals. Some yellow over time, some are thin and pointless, others are thick and protective but harder to use in areas with welds, curves etc.
In my experience a combination works well I.e. thick stuff on downtubes and areas that need the most protection, thinner stuff for contours and areas prone to cable rub.