Figure that the typical incandescent bulb runs at about 18 watts. The 18" T8 fluorescents with 2 tubes runs 30 about watts (2 15 watt bulbs).
LED and fluorescent light produces about 4 times the light per watt of an incandescent.
See
LED lighting – DIY strip lights for a bit on this and links to where you can find out more.
The biggest advantage of LED over fluorescent is that you can use a lower light level that has more directionality to put the light just where you need it.
Replacing incandescent bulbs, or even fluorescent bulbs with LED substitutes doesn't really take full advantage of the LED benefits as the fixtures are for a different type of light source.