Cloaky, my story is similar to yours. I was a very very avid reader before Animorphs. I used to check out books from my school library as if they were candy, a book practically everyday. The librarian once even took me aside and asked me if I was just playing around checking out books and returning them the next day, but it was just that I loved to read.
Anyway, some Animorphs books were in the library and I thought they looked interesting enough for me to start reading them. Not surprisingly, I got hooked right away. Before I knew it, I was in every book fair and library in town to try to find more books.
So, how it did help was that it got me interested in following up and being as dedicated as one can get to reading those books. Before I would just read the synopsis on the back and check out random books, Animorphs got me more focused on what I want to choose. It added to my collection at home which I still cherish. It also got me more interested in animals. For example, when I read Cassie's The Message, I was so intrigued in dolphins and loved to know more about them. Also, ants, I wanted to know the nature of their living and such.
So, yeah animorphs did effect me as a reader quite positively.