I have to disagree a bit here. The color corrector will do a pretty good job of white balancing the video image IF you can find white, neutral gray, and black in the image. That seems to be what the three color wheels are aimed at. Beyond that, they are not really precise enough to do good color correction.
Color curves are much more useful, but you need to think carefully about what you are doing and clearly understand how complementary colors work. The biggest problem is that Vegas does not give you any information about where a particular instance of color in the image lies on the color curve. I have started to have some success by using Vegas’s ability to place a snapshot of the image on the clipboard. I can then bring that image into Photoshop, and Photoshop will tell me where specific points lie on the color curve (i.e. by using a color curve in Photoshop). Using that information, I use the red, green, and blue curves in Vegas to make the color correction. For example, if I have a yellow caste in a portion of the video image, I can reduce the yellow (and the luminance) by bending the red and green curves down at the appropriate point on the curve, OR I can reduce the yellow while increasing luminance by bending the blue curve up at the appropriate point. The ability to center the adjustment at the correct point on the curve and shape the curve gives much better results than I have been able to achieve with the color corrector. You can, of course, also selectively cut or boost luminance for a specific tonal area using a curve. It is not quite as easy as using a slider to, for example, fill shadows, but it can still be done.