It's far easier to think in lumens, rather than in watts, when comparing different types of bulbs.
Traditional incandescent bulbs have roughly the following light outputs:
40W > 450 lm
60W > 800 lm
100W > 1600 lm
150W > 2600 lm
Once you know those figures you can look at the packaging of
any type of bulb and see how the light output compares. So, for example, these 40W G9 halogen lamps are rated at 410 lm, meaning that they produce slightly LESS visible light than traditional 40W bulbs:
http://www.buyspares.co.uk/product.pl?pid=954668
All bulbs should now have their light output, in lumens, on their packaging, so you can easily compare different types.