I certainly believe in a spirit world consisting of good spirits and bad spirits, the reason is because my aunt has seen an evil or bad spirit herself. She is a high school principal, but at the time she saw the spirit she was a vince principal at the same school. She was living in a small apartment and one day shortly after she moved in, she was watching TV, and a black misty/smoky mass in the shape of a person floated thru the kitchen in her peripheral vision. She pretended like it was just her imagination, but then she started seeing it all the time, and this spirit would always talk to her telling her things like "your daughter is lazy and irresponsible, you should kill her", or, " your mother is old, senile and a drain on your finances, you should put her out of her misery". It got to the point to where she would see this spirit day and night in her bedroom, bathroom and all over, and always the spirit would come to her with negativity in thoughts and words.
Well it got so bad, that my aunt finally decided she had to move, so she called one of her brothers, my uncle, to come spend the weekend with her and help her move to a new location. He agreed and got there on friday morning before she went to work, when she got back friday evening, my uncle said, "well i can see why you are moving , this place is haunted !", my aunt, who never told anybody of her experiences before then, asked him whey he would say that. My uncle responded that he had been sitting watching TV during that day, and a black cloudy mist floated up to him and began whispering in his ear to kill his sister, and then kill himself. My uncle, being from the hood, told the ghost to "fuck off", but nonetheless, the experience left quite an impression on him. My aunt moved that same day and has never experienced anything supernatural since that time.
The reason I especially believe this story is because my aunt and uncle, as well as everyone else on my mother's side of the family is EXTREMELY religious. But they are baptists, and baptists don't believe in spirits, so speaking of any type of supernatural occurrences is strictly forbidden. So for my aunt, who is a career proffesional educator, and who has never lied to me in life, to tell me this story, corroborated by my uncle, makes the story absolutely true to me.
So if there are bad spirits such as the one that haunted my aunt, there must also be good spirits and a whole spirit realm. I think what happens and where you go after you die has a lot to do with the kind of life you lived. But I do believe strongly that there is a spirit realm, and I do believe that it is very possible that you could see your loved ones again someday.