Are the students you're referring to still fairly elementary? I'm assuming so since you asked about method books (and I move out of specific method books after elementary, level 3 or so). I think a student who has only been playing for 2-3 years should not be allowed to choose "only jazz" or "only classical." They are too young and musically inexperienced to know for certain that they completely "hate" a particular style of music. I try exposing my students to my favorites in various styles, with great success. For example, in jazz style, I've never had a student who didn't love In the Mood, Linus and Lucy, Pink Panther, as well as pieces in Martha Mier's Jazz, Rags, and Blues books. For classical type pieces, students love playing In the Hall of the Mountain King, Pachelbel's Canon, Bach Minuet in G, and numerous others. There are just too many great classical pieces out there to allow a student to declare that he hates them all (and I'm using the word "classical" in the layman's broad sense of the word; I mean Baroque, Classical, Romantic, Contemporary).
Regarding method books, I like the flow and "security"of using a specific series, building concept upon concept in a very organized fashion. If you aren't happy with the pieces in the method books you're using, perhaps it's just time to try a new series. I absolutely love the pieces in Faber's Piano Adventure series (I use the lesson, technique, theory, and supplementary books--all are terrific!) and also in Hal Leonard Student Piano Library. Hal Leonard's accompaniment CD's are particularly impressive, and my students love them.
Through the years I've also developed quite a list of other favorite supplemental books. I'm just amazed at how much truly fantastic music is available for students.