Berserk, Hajime No Ippo, Fruits Basket, Full Metal Alchemist, Last EXILE, Cowboy Bebop, and Naruto <- These animes are top-notch in my opinion. Berserk for its excellent story-telling and characters, Hajime No Ippo for its consitent quality and ability to hold your interest for 76 episodes, Fruits Basket for it showing that not all Shoujo anime are cutesy fluff, Full Metal Alchemist for it being constantly dramatic and smart, Last EXILE for its spectacular visuals, Cowboy Bebop for its wit and class, and Naruto for being a martial arts show that has actual thought put into it. I guess you can also credit the fact that most of these animes have excellent mangas as their source works.