Glad to see you here. I believe you're in for a real treat!
Web Theme Samples should be very useful to you. It offers 67 different examples of web site coloring, with coordinated backgrounds, banners, buttons, rules, and fonts. You may find a suggestion here for your own personal site but it's an excellent way for you the designer to get some idea of what your client likes, esthetically.
I created a sample web page and show it in each of the 67 themes Microsoft provides in their FrontPage 2000 product. I originally password-protected this directory so that only my colleague could use it for our clients. Later, I relented and decided to offer it to anyone who visits here. It also shows you a real-world example of protecting a directory, as further explained in the topic Web Site Security. Please read that topic if you haven't already.
I used a couple elements of the 'Postmodern' theme for this website, if you look carefully. I am temporarily using its background because it colors well with my other blue background. I also took its blank banner graphic, shrunk it a bit, and then used PaintShop Pro to place a nicer font on it. Ditto with a few buttons I'm using here and there.
When you click on the following link, you will be presented with a security dialogue (from .htaccess). Your userid will be guest1 and your password will be guest1ok. Be sure to use lower case. It's OK to make a mistake because I'd like you to see a special page I wrote to intercept the authentication error. (Note: You have to cancel out of the authentication dialogue to get the error.)
Allow a minute or two for the page to load. It contains 67 5k thumbnails of the various themes. The text preceding the thumbnails was written for clients we send there directly.