You mean lighted medicine cabinets but no other light in the room? Do you have fans that have lights? We have sconces plus the fan, but the fan light on its own is often plenty of light, if there is good natural light in the space. So fan light plus medicine cab light might work in the right space.

Yes, you'll need some kind of room lighting. How much will depend on the size of the bathroom. Also, you might want to check on the replaceability of the bulbs in your lighted medicine cabinets of choice: even LEDs fail sooner or later.

For a powder room, okay. Otherwise you need general lighting. A lit mirror is really for grooming.

To clarify, I have two recessed light in the main area and a recessed light over the tub. If I stand at the sink the only light hitting my face is from the frosted lights built into the mirror. I recall a pro here saying that that was not enough light to properly illuminate your face.

This type of mirror.

Okay that mirror is perfect. My SIL has one in their new bath, very nice. That plus recessed lights is enough. You don't want another fixture to distract from the mirror...look at your example. Looks good.

Found a lighted mirror the exact same size as the bathroom windows. Of course it's expensive but I've got to get it, right? :P The reviews talk about the need to get a dimmer for the side lights... that calms my fears.

I'm hoping those sidelights provide enough light. I got a round backlit mirror thinking "moon" when dim and that I could brighten it so I could have the light I needed. Well, it wasn't enough. I did have a beautiful moonlight effect for a calming shower, but now the new side lights are too bright for that effect. So sad. 

One thing to look for is heating for the mirror so it doesn't fog up. Mine had only a dinky little square inside the moon. Looks dumb but better than nothing.

Oh...let me clarify. The backlit mirror did not provide light for makeup. I had to add a pair of pendants for that. In addition, since the pendants are wired with the general lighting, they make the room too bright now for the moonlit effect I had going before them.

That one is wrong...not the same type as your first picture. You need makup mirror lighting. You will love it. They are fantastic. Plenty of non-harsh bright even light. The 3 bright overhead recessed fixtures are perfect for general lighting. This type:

LED Medicine Cabinet With Defogger, 20/R · More Info