You are absolutely right about having lighting on either side of the mirror. It is the most flattering because it bathes people in even illumination. Good store designers (or those that hire incredibly talented lighting designers) know that if people feel attractive when they try something on, then they are more likely to buy it. Any time there is recessed lighting above a mirror, whether it is in the dressing room of a store or in your own bathroom, you are hit with light that casts harsh shadows underneath your eyes, nose and chin. Nobody looks good under this type of light ... unless you are lying on the floor looking up.
For your bath, find a light fixture that is vertical and linear. This gives you better coverage from the top of your head down to your ... elbows. There are lots of fixtures that use incandescent or halogen sources to provide this kind of illumination. Take a look at the Robbia Full by Artemide and the Dover by LBL Lighting.
There are also dimmable fluorescent sources, like the Emanation by Boyd Lighting, that I think do a very good job, especially when the correct color temperature of light is selected. I tend to recommend a lamp that is 2700K to 3000K (the color of standard incandescent and halogen light). Sometimes I specify fixtures with two parallel lamps, one of which also provides the color of daylight (5000K), like one made by Dreamscape.
We are not seen under much incandescent light during the day, so it’s better to do your makeup and select your clothes under a daylight quality of light. Most of us are getting up and getting dressed before it is daylight outside, so we need to rely on an electric light source to provide an effective substitute. You simply can’t always wear the clothes from the night before. My limit is three times a week.