Great question ! Both are decent solutions, but you may want to add a few more factors in your decision making. Consider the availability on natural light in the space,windows or skylights- more the better. A room with an abundance of natural light improves performance the task lighting . Consider two levels of light for your design, you may wish to incorporate a secondary light source into your design with a soffit above the vanity with recessed dimable downlighting. You should not plan on using Downlighting by itself directly over the mirror as they tend to cast heavy shadows on the face. These can be used to supplement overall room lighting, and used inconjunction with the primary task lighting (with natural daylight bulbs) from decorative wall sconces. As your wife will probably tell you, fluorescent lighting is not recommended for applying makeup.
All that said- Most will say side lighting is better task lighting but...it really depends on the fixtures and wattage of the lamps. A 40w bulb may give you the even wash of light on the face and hair. or increase the size to provide an balanced level of light equally across the face.
also consider the location of wall outlets ( including a vanity drawer outlet to hide the clutter of wires) and... how about adding a switch to control the secondary lighting ( soffits) at that sink location? and additional task lighting in the shower area, a flush ceiling light with 100 watt , 120 volt halogen lamp offers great light for shaving e.g. legs . Choose a brushed stainless steel housing to prevent rust..

This is Hilarious,The light should be placed in a way so that if required they can bathe you in light , we guys do not use any makeup , just shave in the bath but look at the agony of a girl , if she ever wears excess make up due to insufficient light in the bath, she would be the topic of Hot Gossip for a lifetime ,and You wouldn't want your wife to suffer too much Rouge or Make up ?

I take lighting a little more seriously than Vikrant seems to. I would do a combination of recessed lights and sconces, placing the sconces so that they flank the mirrors, with either 3 sconces or 4, depending on how much space is between the mirrors.

From someone that was a lighting consultant: The BEST task light in a bathroom for make-up/shaving is sconces on either side of the mirror with a halogen light bulb. Halogen does come in a standard light bulb shape/size these days--they cost more but, should last longer than a standard incandescent bulb. They also burn hotter because of the gasses that they use in the bulb--so NO closed-in fixtures with these bulbs unless they are specifically rated for such. They'll last longer and be safer overall if the sconces open upward (heat rising and all that). However, just using scones doesn't give much light to the rest of the room. And if you can, I would highly recommend doing recessed lighting for the overall lighting in the room. Depending on the size of your space I'd recommend 5" cans with a BR-65 (or comparable fluorescent) bulb.
Our bathroom is 12 by 6--we have 3-6" cans with 65w comparable fluorescent (6" were all that were widely available when our house was built) over the main space in the bathroom and a vent fan/light combo over the shower area with 1-60 watt bulb. Plenty of light for general use of the space and for cleaning but unfortunately, we didn't build our house and there's nowhere to put the sconce lighting for our mirror without an entire overhaul. I do my makeup and eyebrow plucking with all the bathroom lights on and the adjacent hallway light on also...
Hope this helps!

Hi Amanda , we are so correct you see , it should be enough to Bathe us in Light , that's the Point Corolyn missed .