It is the funniest thing to me that some of you posted that your kids WONT move on from Harry Potter! My DD9 began HP in second grade (I made her wait) and the I made her wait to finish the last 3 books as they were a bit mature. But she finished at the beginning of 3rd and now, at the end of third she is having trouble getting into more books. She has read several 200 - 300 page books, even some young adult fiction, but she just can't seem to pick up another fantasy series. She asked me to pick a book for her the other night and she pointed to a big thick fantasy one - book one of the series..(I forget which one) and said, "just don't pick that one until after I've seen all the HP movies!" I haven't let her see all the movies. I have heard they are quite dark...but ya know what! She is going to see them all and then she is going to get to go see 8 in a few days at the theater...she has seen NONE at the theater! So, I'm giving in and maybe she will move on from here!
As for getting you children to LIKE to read! My advice is to let them read whatever they want.
I read to my 5 year old. I read to her what I want to read to her. And she reads to me what I want her to read to me...but all her independent reading is chosen by HER. She has been reading the Junie B. Jones books for almost a year. over and over and over. And I decided that I was going to let her. Because she loves them. Loving to read what you are reading is so much more important that "what you are reading" at young ages!