If you're interested in battling with others, or trading with people online, or messing around with the new battle mechanics, thats one reason to go with the new one.
If you're only going to play through it for the story and some good old-fashioned single player fun, the GBC version is going to be fine.
It depends what you want to get out of it. Is there anything really new to the series thats making it retain the high scores? Stick to my original GameBoy Colour Gold version, and save the $69.95 Though if it is, i dont know why its getting a 8.5/10. From what ive gathered, it sounds like it's the same game. Ive looked at Pokemon Heart Gold for Nintendo DS and saw that IGN gave it an 8.5 out of 10. I havnt played a pokemon game since Gold version came out all the way back in 2000 (man, 10 years) and i've recently had the urge to play it again.
