Download an UXTheme patcher and then go find a visual style you like.
DeviantART is a good place to start, since that was originally started as a PC customization website. Customize.org is pretty dead now, but there are still a few visual styles and rainmeters worth checking out, although most likely not worth it.
Basically, stick to the stuff they have on DA, some of the most talented people post their stuff there. If you want inspiration, and maybe a few download links, check out pixel****ers. Not much you can download there, but plenty of screenshots for inspiration.
You'll also want to get the registry edit that adds a take ownership option to the right click context menu.
If you don't want to bother with all of that, buy WindowBlinds, does all that stuff for you.