I get home from work last night and my wife tells me my habanero plant has been hit by something. Take a look and one of my habanero plants is nearly leafless and the other one was had some leaves missing as well. Leaves were in the pot, still green and peppers still on the plant. So I dowse them with Sevin dust and feed em some miracle grow.
My wife sends me a picture of the other plant that still had quite a few leaves last night, most of its leaves are sitting in the pot to. I have 2 jalapeno plants and cherry tomato plants right next to them, they are fine so far
What causes what looks like healthy pepper plants to just drop leaves?
Worms, bugs, something in the soil?

Could be anything you listed plus, overwatering, peppers are prone to root rot if overwatered. too much shade, a few nights below 60, calcium deficiency.

Should be able to see evidence of bugs/worms, cut or ragged edges where the leaf separated from stalk etc..

Like rustler said, over watering could be it, especially if they are potted, do the pots have drains? My peppers never really even produce well till the hottest part of the summer.

Yes they have drain holes, have had quite a bit of rain a few days ago.
Treating all plants with malathion this evening.
If it is root rot, can that be remedied or just kiss the plants goodbye?

Leaf cutters?

Yes you can 'fix' root rot a few different ways.

Pull plants from container, with sharp scissors cut roots slightly above damaged /rotted parts, empty soil in pot, scrub pot with bleach / water solution, fill pot with new soil.
Replant within an hour, very light watering.

You can try a fungicide mixed to label directions, some just pour on / take the place of waterings. These can work well and are easier, sometimes if the conditions are right and not corrected root rot will return in a few weeks.
The more effective method is to pull plant from container mix fungicide to label directions, set plant & dirt root ball into container filled with the fungicide mix solution.
Allow to sit while you empty & scrub pot & replace soil, replant as quick as possible, delay watering for at least 3 days.

There are some home remedies using a 3% hydrogen peroxide solution, never tried any.

Treating them with Sevin & malithion if you don't know if they have some pest problem is a great way to further weaken them.
If they have bugs/worms treat that,, if it is root rot treat that, if it is temp, sun or soil nutrient deficiency treat that.

If your pickup is dirty you don't go buy new tires, it won't fix the issue of needing a wash job.
If you need tires, washing it won't help the tire problem.

Thanks. Was reading up on how to cure root rot, if it's not to late. All pretty much what you wrote down, except without the truck tire problems.

I'd say too much water

I'm inclined to agree.
Replanted both habanero plants, and both had good roots, no sign of rot.
This morning both my jalapeno plants have dropped alot of leaves.
No sign of leaf eaters, just leaves falling off plants along with a few peppers.

Too much water(rain). I've seen several trees at work and shrubs dropping leaves a couple weeks ago

I had a decorative plant do the same thing about a month ago. Dropped all the leaves, looked dead, a week later all new leaves were sprouting.

Hope this happens to mine. Not tossing them out yet.