Yup EF-S.
I held off on buying EF-S but since I have a 40D and 20D now, it makes sense. They hold value well, and I'll have the 40D for quite a while anyway. If I end up with a 1 series body in a few years, the 40D will still be good backup and I also plan on getting the 17-55mm f/2.8 IS EF-S lens as well.