I was a Civ 1 and 2 fan. Want to get back into the latest versions, but don't have much time now.

About skins/themes... Windowblinds will work with Bryce, and does so rather well. Some of the skins in Windowblinds add additional features to a typical window, for instance every window can have an "always float above other windows" feature. And yes, it does a lot more than just skins. Back in version 3, all my windows had a glass/translucent look. The newest versions I haven't yet discovered all it's features yet. Windowblinds is part of a set of skinning product from Stardock. Each product can significantly alter Windows so that it no longer resembles Windows at all. Windowblinds is Stardock's most visual product, though, and I recommend that be the starting point for anyone wishing to skin.