I’m not the first one to realize this, but there’s something wrong with color management in Firefox. Look at the following screenshots.
This is the original picture in Aperture, with colors exactly like I wanted:

Now the same picture in Safari

And now for something completely different: Firefox

In this particular picture, I used saturation to give strength to the moment, only to find out Firefox decided to wash out my colors.
The technical story here is that our monitors can’t display every color, so we have color spaces, and Firefox ignores them. Good news is that color profiles are supported in the Firefox 3 beta, though not enabled by default. You’ll have to open about:config and switch the gfx.color_management.enabled variable to true.
Bad news is, that will only work for you. If you’re trying to show your pictures to the rest of the world, they won’t see the same colors.
To learn more about this: