There is no perfect light, but there are some really great lights available today that are great for different budgets and uses. Here are the ones you should be considering.
Dimmable CFLs - £50
This is the best I know of for a very low cost studio kit. These lights give out a decent quality light, although just like most other lights they usually have some color cast. They are cheap for the power you get, easy to use and have 5 levels of dimming, which is not ideal but not that bad. They don't heat up the room too much and don't have flickering issues. My choice for lighting most studio shoots. They aren't great for travel though, they take a long time to set up and they are very fragile. I have four of these and they are fantastic in the studio.
Yongnuo YN-160s - £24 plus batteries and AC adapters
This is the best option I know of for a low cost travel and outdoors kit. Superb lights with a high output for their cost and size. Can be connected together using various accessories for additional power. Very versatile, but for some shoots these won't give enough power. Don't be tempted by the larger YN300 (which is crap) and the YN600 (which is good but makes unacceptable fan noise).
Big-ass reflector - £20
This is a must have for me. It's super useful for bouncing and blocking light, and very easy to travel with. I have one, which has so far been enough for most shoots.
Halogen lights. They are very hot (sometimes even a fire risk), bulbs can die in hours and they use up a lot of electricity.
Home-use LED lights. They don't have a reliable color.
Fake “As Arri” lights. They are heavy and overall not great.
CAME brand lights. They have an unbelievably loose quality control and sell lights that promise 100w and only really give 45w.