What kinds of bulbs can be used in the recessed can lights in my kitchen? My electrician says I must only use Halogen bulbs (50 watts max), and others tell me I can use any bulbs, including LEDs.

There are LED bulbs that are designed to be replacements for halogen bulbs. It is fine to use the LED replacement bulbs, because they have very low wattage. As long as you are not exceeding the 50-watt limit of your fixtures, it is fine to install LEDs. To see the best LED replacement bulbs, you should take one of your existing bulbs to a lighting professional at your local ALA-member lighting showroom.