I know I'm not the last person to say this, but Yu Yu Hakusho, Trigun, Outlaw Star, Rurouni Kenshin, Dragonball (not Z or GT), Ronin Warriors, and any early Gundam are must have watches. (Also the dubbed and subbed are great for all of these)
Current anime that are great include Baccano (top of my list), Sora No Otoshimo (becuase of the fan service), Durarara (anime should come out in around 2011), and once High School of Dead and Bakumon come out in DVD (whenever that will be?)

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