SD Card - GoPro Hero HD I have seen a lot of comparison about which microSD card I should take if I own a GoPro Hero 3/4 but none of thoses articles mension the original GoPro HD.

So is it worth buying an expensive one (30-40€ - 32 Go) or just a normal one (class 10 etc... at 16-20€ - 32 Go) is perfectly enough for filming in 1080p without having any downgrade in quality.

Thank you in advance :)

PS : I know there is a list of SD cards on GoPro website, but they may link overpriced SD card for the Original HD, that's what my question is about :)
You shouldn't notice in major downgrades in quality from a slower card (which I'm assuming is the main difference between the "expensive" cards and "normal" cards you mention). Higher speeds are required for newer cameras (like the more recent GoPros) that shoot in a much higher resolution and/or frame rate that need to be able to write a lot of information very quickly to the card. You should be more than fine with a class 10 card for the original GoPro HD.