Yamamoto Zenjirou to Moushimasu (YZM) and Shinrei Tantei Yakumo (STY) are both mangas wherein the protagonist (s) have the ability to see and speak with the dead.
Whilst YZM is a light-hearted shoujo style manga where the main character, ten year old Hotate, can see ghosts and makes friends at her new school due to these ghost seeing abilities, STY is much darker.
STY's main character Yakumo is in high school and his ability to see ghosts is due to his single red eye. Most people find his red eye eerie and discomforting and so he covers it up and doesn't use his ghost-seeing abilities that often. After having his help requested by a girl named Haruka he discovers that not everyone is frightened of his eye.
Overall the two manga are completely different in mood and characters but if you enjoy paramormal manga with a hint of romance then they are both very enjoyable. As there aren't many ghost mangas they are well worth a read!