Steins' Gate is a must watch
Grisaia VN is great, but i don't think i could see the same quality in anime (obviously)
there's tsukihime, though i haven't watched it myself so i can't give any words. nvm
Majikoi counts too, but i say you just need to read the VN. it's one of the best. (not the anime though)
and, usually vn-adaptation anime (not all, with exception) would make you cringe rather than that feeling of "this is friggin awesome!". so, i'd advise to read the VN first then the anime.