I recently bought 8 LED flashlights at Walgreens for $5. They are very bright. I left one on for hours inside a piece of equipment and have yet to see any significant drop in brightness. About the only advantage of incandescents is that they can be easily dimmed. Hopefully they will be drop in compatible in those applications too.
The LED will put out way more light than your 12w incandescent.
To save power (almost all of it) chop the 12V (12V dimmer) until the output is comparable to what your had. The dimmer can ran at any frequency you want so there will be no strobe issues.
You need to buy CFLs/LEDs in the color range you like. These days you can get any color you want, see: http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_color
LED lamps are available in color ranges as well. I like the 2700K - 3000K lamps, which look very similar to incandescents.
I'm very anxious to see some real world results on these LED "bulbs." In theory, CFLs last a long time and produce as much light as an incandescent, but in practice, they only do so under a specific set of conditions. Further, the low-cost volume manufactured CFLs tend to use component on the hairy edge of their rated specs, further distancing practice from potential.
If LEDs can avoid the same pitfalls and genuinely last and produce quality light, then I can see a number of changed paradigms in the lighting arena. Most folks talk about the energy savings, and that's certainly the most important aspect of these new lights. But there are potentially other advantages too.
There are a number of areas where LEDs have already turned lighting into permanent components of the system. You don't expect to change indicator lighting anymore, for example. If home lighting can truly end up as long-term and reliable as, say a plumbing fixture, then interior designers can have much greater flexibility without unduly burdening homeowners with near-impossible to access bulbs.
The life of LED itself may be 25000 hours but what about the control circuitry built into the bulb. I am sure there will be some control circuitry to convert utility voltage to 12V DC. Will that also last till the lifetime of the LED?
That's a good question. The answer is that it isn't an issue if the supply is designed with that type of source in mind. Because it will probably have been considered a requirement for the lamps to be dimmable, it won't be an issue. If they haven't considered this then who knows.
CFL's are not a replacement for standard incandescents. I have yet to see a CFL that lasts longer than 2 years. On average I need to replace them once per year. When you consider how much more energy goes into making them and that they contain mercury, they are in my opinion an environmental disaster. I have incandescents that have been installed for 11 years without failure. That's even in toilets and hallways where they are frequently cycled. LED's themselves should meet 25,000 hours or even 50,000 if they are kept cool enough, but I wonder about whether the switching converters that run them can meet that considering the price point they will be built to. Also consider the additional EMI of say 20 switchers/lights running in every household at night. Shortwave and AM radio may no longer be what it was :-) .