Many issues here. Let me go over in as much detail as possible:
Background: I love energy efficiency, and when doing my kitchen researched this LED Vs CFL vs incandescent lights extensively. Notice there are also permit (legal) implications, depending on which state you leave (CA has Title 24 for example).
Connector types: There are several connectors that make the decision of which light you can use tricky. the main ones are
Edison: The screw type, accepts CFL, Incandescent and some LED bulbs
Pins (2 or 4): Accepts florescent. Was invented mostly so that for permits purposes, they can make sure you are installing an efficient light and will not go and replace the CFL bulb with an incandescent one after you pass the permit.
GU10: mostly used for high voltage halogen
GU5.3 Bi- Pin: mostly used for low voltage halogen
High level rules:
You never go with incandescent when it is incandescent Vs CFL (Edison, screw system). LEDs are getting there, but not enough to justify the price and their light output is very low.
You can only go with pin florescent if you have a florescent "hw". that is the only thing that you can plug there by design.
Never use Halogen. If it is a GU10 (line voltage), get a $20-$30 LED (MR16). you get 4W Vs 35W. Light output is lower, but you can get HW with simply more heads. Replace 3 halogen with 5 LEDs and you are fine in terms of light and energy savings
If the halogen is a low voltage, things get tricky. You can just replace the head with a 3-5W bi-pin LED. they run $10-$20. They problem is that you need to make sure your low voltage converter will work. converters have what's called "minimal load". For most of them, they expect a 35-50W halogen so they have a minimal load of 10-20. That means that when you plug a 3W LED, they may not kick in. you solve it by either using a remote transformer that feeds "enough" LED bulbs, or get a transformer that is "led" designed, but really all it means is that it has a minimal load of 3w and goes all the way up to something (I have a 3-60W for mono-points).
Lat general tip: do not mess with dimmers. Just on/off.
My personal choices:
For kitchen recessed light I got LED LR6-GU24. It is 12W, think that the florescent way would suggest I put a 23W bulb for each of these (I have 7). That means 50% saving. Same light output (they say it is 65W equivalent, but it feels like closer to 90W). No one can tell it is LED BTW, it is bright and even (not a "pin" of light, and well spread).
Cost efficient: great! less energy, and upfront cost was the same as getting a florescent can combination. (you may get cheaper florescent if it is not for a permit and you do the Edison type)
For a bat lights I went with 3 mono points. Each has a transformer built in. I did not (suggest you never) buy "LED" lamps since you pay a huge premium for getting the LED HW. I just got the transformer with minimal load of 3W. I then threw away the GU5.3 Bi- Pin halogen and got Maxxima LED MR16. They are very good price (value) company. I compared the light to a $30 GE and these one are just as good. Notice that at 3W it is indeed just ambient light. good for over the bar in addition to some other light in the room. If you need more power, get 4 or 5W bulbs. see maxxima site
For spotlight lights in the center of medium size room, I went with much cheaper "line voltage" fixture from Lowes. These fixtures expect GU10 halogen (25-50W). I got in this case a the more expensive $30 LED GU10 bulbs (GE, at home depot). They are great, but I hope you can do better on the price. I have 5 and for medium size dining room, correctly targeted, it is nice light to use while eating.
Do not use a non-dimmable CFL with a dimmer. It shortens the CFL's life, and, in rare cases, a dimmer operating a CFL could result in fire. Change it out with a switch to be safe.
Dimmable CFLs aren't as good as incandescent for dimming. Their lowest settings are nowhere near that of incandescent, but they are good if you want the option to save on power and still be able to dim the lighting. Sometimes you will have to turn up the light to get it to kick on and then dim it. They can also be audible at their lowest setting. If you buy some, save the receipt as you may not like their drawbacks.
Best Answer
The short answer is to check with the bulb manufacturer. Ambient temperature and use case requirements may also be mentioned on the box/packaging.
The long answer is that it depends (as always eh?). From what I could find online, CFLs and incandescent bulbs are actually MORE sensitive to LOW temperatures than LEDs. So in your specific use case, I would think you would be fine in using an LED bulb.
That being said, keep in mind that there ARE certain environments where LEDs may perform worse -- particularly in settings where the ambient temperature is very high, resulting in overheating of the LED package and eventually leading to device failure. I think most manufacturers are getting better at heat sink designs anyway so this may not be a concern later.
-M