The ATI video card does not take up all that much power (only 35-45 watts depending on the model that you have). They have purposely reduced the amount of pipelines so that they may reduce the amount of power.
NVidia, on the other hand, is a power hog, and the higher models take up close to 70 watts.
The most power hungry component of my PC is the P4 3.0 GHz processor which takes up a total of 68 watts.
The problem is that the 5 LED cooler-master fans flicker after the OS is loaded, but I do have enough power... I have looked into it, and I have run into a few articles that have said that the new P4's with hyper threading (2.8 Ghz, 3.0 Ghz, and 3.2 Ghz) causes the fans to flicker... I am planning on breaking the lights on them on purpose rather than buy new fans....