What LED light bulb should I get ?

Question : What LED light bulb should I get to replace my 100w incandescent bulbs ?

Answer : Probably LEDs around 25w or more

12w LED Cornbulb

Lumens : Most people probably want to use lumens as their reference rather than watts. This is the measurement of brightness. The more lumens the better.

Lumens of an incandescent 100w bulb : around 1600 lumens
An incandescent 100w bulb is estimated to have around 1600 lumens. With LEDs you will probably need 25w or more to match or beat that amount of lumens.

Other things to consider when buying a LED bulb

Color temperature
bulbs with a lower color temp are more yellowy (warm), and ones higher have a bluer white (cool). Warm is around 2700K. Cool is around 6000K. Personally I think I currently prefer something around 4100K but this might not be a common option (often it's either warm or cool only). 'Warm' is meant to be the equivalent of the old 100w incandescent bulb most people had (giving a yellowy white).

35w CFL bulb

Base/Cap type
Usually this is either standard screw bulb (ES, Edison Screw) or Standard Bayonet Cap
Standard size screw bulb code : E27
Standard size bayonet bulb code : B22

What happened to CFL as energy efficient bulbs ?
They are still around but if you are 'green' then they have been superseded by LEDs as the 'green' bulb of choice. CFL's contain mercury, and LEDs also tend to give more lumens per watt, meaning less watts needed. IKEA now only sells LED bulbs.

Why is everyone with LED bulbs in a dark house ?

12w LED aside a 35w CFL

Most LED bulbs widely available are usually below 10W, which is like having 40W incandescent bulbs. Not enough lumens. 25w+ LED bulbs are not common in shops. You can get them easy on Amazon/Ebay etc.

Size of LED bulbs :
Currently LED bulbs can get very big as the watts go up compared to incandescent bulbs. A 20w bulb might be 15cm long. I guess over time they will produce smaller versions as technology improves.

My advice if buying LED bulbs :
I am still a novice in this myself but I would say treat yourself to lumens. Even higher than the old 100w incandescent equivalents (1600 lumens). I would go for maybe 25w+ but watch out about size. They get pretty big around that wattage.