There are endless articles, blog posts, opinions, theories, philosophies on the topic of color. I've changed my personal brand color palette at least 3 times in the past 15 years. In fact, just recently, I changed my "logo" to what's on this page because the colors suited my mood (or where I like my mood to be) and these colors continue to make me feel happy.
I don't expect everyone to love my colors, but I hope to attract those clients who have a similar positive outlook toward life.
Even as a designer, I do not presume that I know how my client responds to color. I will offer my advice on how your market may be responding if I know a color isn't going to work for whatever reason.
Of course, I'll want to offer complementary colors to whatever your logo is, if you already have one, to maintain your brand.
However, if you want to change the look of your website (or anything in your life, for that matter) color is going to make a difference.
Here's a great tool for helping you make your color choices: Adobe Kuler
Not only is the page beautifully designed, it's really fun to play with you. It's free, and all you need is an Adobe ID... also free.
p.s. Adobe has some other helpful free tools you can access with an Adobe ID.