This tutorial is for those of us with Vista. The programs mightn't work on other OSes so you'll have to experiment. Win7 can do this automatically so the tutorial is somewhat redundant.
Here's how to make your desktop badass, all in an less than an hour's work.
Step One: Finding your backgrounds.
Okay, make a new folder on your computer. Give it a name of some significance, so you'll remember what it's for. For this example we'll just call it Wallpapers. Next, head online and find a whole bunch of great wallpapers. Personally I find all mine at 4chan, but the place isn't family friendly so if you don't want to go there, Google searching works wonders. Get as many as you can find and stick em all in the Wallpapers folder. Make sure they're all .png, .bmp, .gif or .jpg. Go nuts here, just get as many awesome backgrounds as you can find, don't feel limited.
Step Two: Setting up the auto-slideshow.
Now you need to download a program. You can pick it up here: http://www.wallpaperchanger.de/archives ... 0702xp.zip Now unzip it to wherever you like, it doesn't matter. Go into the folder and run Wallpaper.exe.
Once it's open, go to the button on the top-left that says open/add. Use the browser that appears to locate the Wallpapers folder. Enter it, then hit ctrl+A, and then Enter. If you click the Apply button, and then the Save button, and FINALLY the Start button, your desktop will automatically cycle through all the pictures you put in your Wallpapers folder. By default, it takes something stupid like 15 minutes to get to each next picture, but you can change just about anything in the options menu.
Step Three: Pimpin' up your taskbar.
This is easy. Just download this: http://www.stardock.com/products/object ... nloads.asp Then install it, finally run it. It's basically a more badass version of the taskbar, and if you don't like it then no worries, you can customise just about anything with it. You can even make it so the normal taskbar disappears entirely, and you only have this new smexy one.

What I've put here is how I've done everything, but to make your desktop really yours, it's probably a good idea to mess around with the settings of Wallpaper Changer and ObjectDock on your own for a while, and customise both applications to your liking.

Optionally, you could also look up and download something called RainMeter, which puts lots of cool and helpful application-like things on your desktop, but personally I dislike it because I like to have my desktop clean and with minimal fuss on it.

This is the superior tutorial for getting a steaming hot sexy desktop;

Get windows 7.

Mine is significantly cheaper.

I'm a student, I get Windows 7 ultimate for free.

So mine's cheaper both in effort and money, duh.

Well so do I, but you've been here longer than I have. You know full-well the majority of these people aren't getting an education.

...

Can't top that.

I prefer RocketDock

WinXP 4 life

Combine Rainmeter and Rocketdock.
It's awesome.

fences, hide all icons, hide taskbar and get cool wallpaper

I just tried this and Snoble is oh so right.