I was never really convinced by touch screens until I acquired a touch screen MP3 player. Now I wouldn't go back. I'm still not sure about their application to photography though. Wheels and buttons are still usable even if you have a camera with a VF held to your eye - not so a touchscreen. Also, how would I stop my nose changing the ISO?
If you are composing via a rear monitor with the camera held away from the eye it might be more feasible but even then I'm not sure how you could hold the camera for shooting and change settings on a touch screen, something I can do easily with the buttons and dials on the LX3.