Actually, k brings to mind a few other considerations. My 40D came with a 28-135 IS lens. That seemed like an odd lens to bundle with that camera, but it turns out to be useful every once in awhile. If I'm walking around at an event, like maybe a car show, sometimes I'll take the 10-22 for a few dramatic scene-setting shots, and then use the 28-135 for just about everything else. In some landscape situations, I need both the 10-22 and the 17-55. In fact, I need them both so much that I wouldn't mind having a second body just so I could use either one quickly.
Back in the dinosaur days of 2004, I had the original 18-55 wonderplastic kit lens on a 20D. That thing got a lot of grief from reviewers, but, it had its uses. First, in bright light, you could stop down far enough that it wasn't too bad for sharpness even in the corners. DxO took care of the remaining distortions. So it really could produce decent images. It was also small and light, and I really wouldn't have cared if it got scratched, stolen or broken. If it hadn't had a rotating front element (making filter use a pain), I might still have it. Just for high-risk situations, or when bulk would be a problem.
Honestly, these types of decisions are never really cut and dried. And, I'm sorry we haven't helped much with your original autofocus question.