I just ran into the best color comparison tool I have ever seen. Adobe Labs has released "kular"; which is easily the most useful app for me as an user experience designer. What kular does is allow you to create groups of colors based on a number of different formulas, allowing for excellent color groups extremely quickly. This allows you to create groups that are distinct and beautiful without spending half your day in Photoshop with a color picker. Thanks Adobe, this is going to save me a lot of time.