Free/Shareware Customizations for Windows

[Morluna]

I've been through a smattering of free trials for software like WindowBlinds, Bootskin, and other software created to customize the look and feel of Windows, but I was wondering if there is any software people could suggest that will do the same kinds of things... without the twenty or so dollar charge. I don't expect super fancy personalization... just anything that will allow me to import themes of any sort. Free is good, obviously... but feel free (lol pun) to make suggestions of purchasable software as well. Honestly, Windowblinds is about the only one I can even think of. Surely that's not all there is.

Is there anything I should know about that you can think of? Thanks in advance for sharing!