Energy Efficient Home Lighting

[RealPerson]

We have a bunch of traditional energy sucking recessed can lights in our house. I would like to make this a whole lot more energy efficient, but I am somewhat confused by the options.
My questions for the best ROI are:

1) is it best to simply change the bulbs or retrofit new can light fixtures?

2) if retrofitting new can light fixtures, what would I be looking for?

3) if keeping the existing fixtures is best, which bulbs do you use to replace the old ones?

4) has anyone calculated the ROI to see if this even worth doing?
It seems that there are so many options these days, that it is hard to make a choice. Your knowledge, experience and advice is greatly appreciated.

[George the original one]

I haven't worried too much about ROI. I'm more interested in brighter light with long lifespan, so I've been replacing lightbulbs with LED bulbs, usually increasing the lighting level. Spotlight bulbs where I want directional flood light, but the LED bulbs with diffusers elsewhere.
An LED floodlight in a torchiere shining up to a white ceiling works wonders for broadcasting light into the nooks & crannies.
Drawback so far is that the LED bulb colors are on the cold side and the floodlights are very directional (no diffusion). That cold light can be minimized with a few warm-tinted compact flourescent bulbs in strategic places.
I don't have can lights, but suspect you'd want to use the LED bulbs with diffusers.
Remember, though, that your electric furnace, A/C, fridge, electric water heater, CRT television, and clothes dryer are the main wasters of electricity.

[Noob]

I just posted something similar in another post. There are solar lights. Now these are not the dinky rechargeable ones at walmart. They work on the same principle as a periscope. They just reflect light down into your rooms only kind of amplified if that makes sense. The down sides is they can only be put on the top floor of your house, and they only work during the daytime, but for those rooms upstairs, you'll never need light in those dark rooms during the day and save yourself some money there.
Also if you want to spend some money to see how to save money.. Most solar power companies will come out and do an audit on your home. The price ranges from like 400-600. They will check your entire house to see where you are wasting energy. From insulation to lighting to windows. They check it all.
You can also check out solar lease programs. I'm thinking of doing this one myself. You basically sign a 20 year lease to let someone put solar panels on your roof and in return you pay them for your power now and get it at a locked in discounted rate for 20 years.
I posted this reply in two different posts so I hope nobody thinks I'm spamming or promoting some company cause I didn't put any links. I just really believe that getting off the grid is the best way to go. Solar, Hydro, or wind. It's free, why not use it?
-Noob

[fiby41]

3) CFLs

[ThriftyRob]

If you research LED lights you'll generally find there's a LED version that replaces traditional light bulbs. You need to know what the bulb type is (it's usually on the glass somewhere). We had 12 x 50W halogen downlighters in our kitchen/dining room which would be on maybe 7 hours/day in winter. I replaced the bulbs with LEDs, rated at 4W each and the energy saving was substantial (except we probably used more gas for room heating!).

When shopping for LED bulbs look for the colour temperature – usually described as warm white or cool white. The ROI is generally positive because LEDs have a much longer MTBF compared to traditional hot lamps. Most folks I know have replaced their lighting with LED and would say it's a no-brainer.

[jacob]

LEDs have come a long way since the beginning of this thread.