The ones I consider to be such are...

'Clannad' / 'Clannad: Afterstory' (One of the most EMOTIONALLY well-balanced and breathtakingly executed story-lines I've EVER seen in an anime) -- http://myanimelist.net/anime/2167/Clannad

'Kanon 2006' (the only way to describe this anime is that it is simply BEAUTIFUL!) -- http://myanimelist.net/anime/1530/Kanon_%282006%29

'Kemono No Souja Erin' (EXTREMELY different from almost ALL the anime out there, its original, brilliantly written and executed, very emotional with a changing but yet at the same time easy to follow without dumbing it down, plot. And the imagery and art are FANTASTIC!) It seems like a kids anime but ,trust me, it gets very mature, complicated and even slightly dark as time passes in the series! -- http://myanimelist.net/anime/5420/Kemono_no_Souja_Erin
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To show that my opinion is actually worth something, as in "I've seen a fair amount of animes and I'm not just picking these because of not having watched many" ; here's my list --> http://myanimelist.net/animelist/animesthabomb
@Kaung -- Why did you copy and paste from your other answers! Couldn't you do it some other way besides copying and pasting? here's a link to where you used parts of the EXACT same answer ---> http://answers.yahoo.com/question/index;_ylt=ApV_jqyDHGT.5fc_OCuh3Jrty6IX;_ylv=3?qid =20121212234344AAIyFC0