Birdy

Cowboy Bebop

Dragonball

Flame of Recca

Gundam Wing

Hunter x Hunter

Inuyasha

Mononoke Hime

Oddments

Outlaw Star

Ranma 1/2

Rurouni Kenshin

Trigun

Yuu Yuu Hakusho

Sharp as a tack!
Sigh, there's no escaping the fact that Ranma is a bit of a meathead. Therefore, to earn this expression from Ranma, somebody must have done something spectacularly idiotic.
 
Added: 4/5/09 From: eBay canuckmunk
 
Sharp as a tack!