Other than Anbu members, I'd say Shikamaru. I mean come on man, he utilizes shadows for attacking purposes. Hes the most strategic. An most intellectual.
Anbu members, Sai, Gai, Tenten, Lee, Haku, Kushimaru(needle-sword guy), Kankuro, Shino, some Hyuuga clan members, Shikamaru.
Even these are far from the traditional ninja definition (the manga does not have to be about real ninja btw), but atleast their abilities or appearance is more fitting than dropping a freakin meteor from the sky or glowing bright yellow.
hmmmm .... no one really but to have something close to a traditional shinobi, it will be a combination (something from each character).
- Danzo's view of shinobi.
- Kakashi's mask.
- Minato's movement.
- what you mentioned, Itachi's Anbu uniform and katana.
but if i have to choose ONE character from this series ..... i would probably choose Minato (ice cold and going fast slashing the enemies before they realize what the hell is happening).