Thanks for posting. What plant to start with really depends on the conditions your mother can provide in which to grow one. If she has a bright, sunny window that can be covered with sheer curtains during the hottest part of the day, I would go with a Cattleya or one of the Oncidium intergenerics. I would steer you toward the intergenerics myself; they're gorgeous, grow quickly, and aren't fussy. But again, they need bright light to rebloom.
A lot of people start with Phalaenopsis (moth orchids) because their light requirements are much lower than those of many other orchid plants. An east window with no direct sun would do just fine for them. It's really up to what you think is attractive and what kind of conditions your mother can provide.
As far as misting goes, many people mist their plants early in the morning to provide some humidity, especially if they run air conditioning which really dries out the air. Be sure to check out the CARE pages for general orchid-growing how-to's.
Hope that helps some!!