In 1.8 I copied the DarkOrange theme folder in App_themes and renamed it BlueOrange. Then recompiled and changed it in the 1.8 admin. So far so good.
Then made major changes to the styles.css but had some issues with inheritance but overcame those and the site looks pretty decent on localhost.
When I went to test it on a remote server I noticed two things -- webconfig references the DarkOrange theme and the skin file has the same name and everything in my new theme.
Should I change webconfig, should I change skin file names? I think this is what is giving some of the funky visited links not being visible effects.
BTW, That styles.css is sooooo huge I was thinking of breaking it up but I don't have time to deal with that. I did however compress it a lot with CSSDrive.com compressor http://www.cssdrive.com/index.php/main/csscompressor/ -- just compressed in pieces with medium compression and left the comments in. Also did a CSS validation at w3 after compressing to be sure that evry thing still works. It validated but got a big bunch of warnings about duplicate properties in tags -- which I may be able to fix if I understand this skin thing.