I'm on the fence. There are things I like about both and some things I don't like on either. I like the original's intimidating look, as someone said on another board -- it's "iconic, gothic and sinister." It's more animal-like, and the back neck area on the long cowl looks incredibly tough. He's actually wearing a cowl. What I don't like about it are the cape clips, the overall rubbery look of the suit, the immobility. It recalls the suits of the previous movies.
The DK suit is more modern, practical, tactical. He can move a lot more freely and the figure is also more poseable. But I really think the DK suit will remain specific to this film. The DK suit and cowl construction really point to a motorcycle outfit, and that's what he uses it for in the film. The new cowl functions like a helmet and the new armor is obviously inspired by motocross gear.
In many ways, the differences in the two suits remind me of the differences in the Michael Keaton outfit, although a lot less extreme back then, between the first and second Burton movies. The second suit was more practical, more modern, more like armor and less gothic. Coincidentally, in Batman Returns, the batmobile is also destroyed and Batman, like in TDK, is able to escape by way of a kind of bat-pod that breaks away from the batmobile.