Hi there, DaiMacDaddy.
It's obvious that you're just looking for a few good ideas to get started off with, and not a comprehensive ten page history of the underground culture that fostered Linux.
That said, what Y'Dobon said is absolutely true and the philosophy of the open-source world is an interesting study.
For those of us in the real world, however, I'd suggest you muck around with the following applications.
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The Gimp - An open source answer to image editing, it has a lot of the features of PhotoShop, such as layers, channels, etc. Though it lacks "publishing" tools it makes up for it with multimedia and web tools.
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AbiWord - A word processor. It opens M$ docs. Handy, yah?
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Gnome / KDE / Enlightenment - These great window managers let you customise your X-windows desktop to the extreme. Gnome and KDE both have great file-managers and web browsers, and a handful of office programs.
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Bochs / Connectix Virtual PC - These let you run M$ Windows in a virtual machine. Though VPC is commercial, it is the better of the two. The handy thing is, these actually allow you to access a windows "machine" - albeit not a real one - remotely using X-windows over a network. That means you can set up one good, powerful, unix server running VPC and a few dozen cheapo boxes that barely run X-windows, and the cheapo boxes will all run Windows and linux software on the server as fast as lightning.
Anyhow, for more info read the LDP (Linux Documentation Project) for specific things you might want to do. Gnu/Unix has an answer to every commercial application, from Visio to Excel.