Instead of giving you custom-made desktop themes, I have decided to give you all the stuff to make you own desktop themes.
For wallpaper, click on your favourite chick:
For screensavers, please check out Joan's Voyager Screensaver Download Place
Here are some Voyager cursors, some animated, some not. One of them beams Janeway on your desktop! Very cool.
Here are some general Voyager icons (including Borg)
Some Seven of Nine only icons
And some icons depicting all the Voyager characters, which I stole from somewhere (just like everything else of course).
A bunch of Star Trek fonts
You don't have Windows Plus? But you want to change your icons and desktop fonts anyway?
Click here for an explanation on how to do that. (advanced Windows users only.)
You're an apple user? I can't really help you, but you can find some neat stuff at Kaleidoscope.