I was at a job site this morning where the electrician was installing undercabinet lighting for my clients current kitchen. Such a small thing that makes a huge difference! Until LED comes along a bit more, my favorite is still Xenon for the soft task light it provides by washing your backsplash and illuminating your work surface.
This article explains the types of under cabinet lighting and what each can do for you. http://www.remodelingmyspace.com/kitchen-remodeling-ideas-how-to/kitchen-lighting/under-kitchen-cabinet-lighting-ideas.htm
Also consider in-cabinet lighting for glass cabinets. We are currently working on a kitchen in which the backs of the display cabinets will be done in mosaic glass tile and then lit from above. Will be a stunning view from the dining room when entertaining.