Halogen is just a subtype of incandescent, nothing dramatically different. It will be fine UNLESS the halogen can is low-voltage, in which case it may require a special dimmer.

in which case it may require a special dimmer

Emphasis on may. Low-voltage dimmers are much more expensive than regular dimmers. We didn't know any better and put a regular dimmer on our two 50-watt halogen lights in the kitchen and it works perfectly -- no hum.

Dimming low voltage rules.

1 - some low voltage fixtures have electronic transformers that state that they can be used with regular dimmers.

2 - some low voltage fixtures have electronic transformers that need the most expensive electronic rated low voltage dimmers.

3 - the rest of low voltage fixtures have magnetic transformers that MUST use magnetic low voltage dimmers or else the transformer or dimmer can fail which can be dangerous.

Hum is not the only concern. I've seen transformers that melted and could have started a fire in the right surroundings. Everything appeared fine to the homeowner till they just stopped working.

Usually a magnetic low voltage dimmer can also dim regular line voltage but most definitely not the other way around.

Dim, thanks for posting the rules. I'll definitely check what I've got when I get home (assuming it hasn't melted and burned the house down by then :))

Just a suggestion -- I would put in two different switches, especially since it is a guest bathroom. When entertaining you can leave the sconces dimmed and the ceiling light off. It also gives you more flexibility in lighting.