Which globes are more efficient and cheaper to buy, install and run? Flouro tubes or compact flouro lights? (the curly ones)

Also are there skylights that don't let in too much heat?

Efficiency wise there's not a lot to choose between Compact Fluorescent Lamps (CFL) that directly replace regular tungsten lamps and fluorescent tubes with ELECTRONIC ballasts (regular magnetic ballasts are not nearly so efficient). Install whatever fits in your application.

The best lighting technology for efficient energy usage is LED, but these are currently expensive and only available in relatively low outputs.

Skylights are a good idea, provided you have a blind to regulate the light. You can get heat reducing glass or stick-on film (like that use on your card windows) to minimise heat gain.

I haven't seen them in Thailand, but the Solartube skylights are a great retrofit solution, and are well insulated. It has a flexible mirrored duct from the skylight to a 24" square diffuser.

Several small ones usually work better than a single large one for providing light, due to the issues Crossy alludes to.

Thanks guys