Changing diffrent Fonts/ themes in win 7..

Hi guys, iv always had a hard time figuring out how to customize my display just as i want it....I know how to change the fonts and sizes but im confused as to what each one is actually changing, iv kinda figured it out but i was hoping someone might be able to guide me to a website that shows what an inactive title bar is for example?

Iv also been trying to get a new them installed, in particular one that has a display of Northern Lights? Again i know how to get the display changed but how about installing one that changes the start menu, toolbars, colors of the text and icons, woldnt that be a theme?

If anyone can share there experience as to where to look and d/l anything that can help me achive this would be greatly appreciated!!