Years ago when I was trying to figure out what you're trying to figure out Cheyenne I found the following web site cleared up a lot of confusion for me.
http://www.richinstyle.com/masterclass/lengths.html
The one thing I do differently than richinstyle.com is I purposely use 100% in the following rule instead of 1em.
a,body,dd,div,dl,dt,form,h1,h2,h3,h4,h5,h6,ol,p,td,th,ul{
font-size:100%;
}
The reason I use percentage rather than em there, is because the em unit there, when used as the base size, tends to result in drastic font size changes when a person increases or decreases the font size in their browser. Using 100% instead in that rule alone (using em pretty much everywhere else) results in more gradual linear font size changes. At least that was true a few years ago when I did my testing then.
The majority of the CSS sample template I posted above is based upon the richinstyle.com master class recommendations. Again, they very well may have changed their recommendations since I perused their pages.
I've bookmarked your cableguymom.com web site and will check it out a little later on tonight or over the weekend. Right now I'd better get outside while it's still nice out so I can get a little yard work done.
John