STL,
We did this a few months ago but I can't find the thread quickly to supply a link. Suggest you do a search on Linux and you'll find it.
Couple of things you say:
Is Linux a real alternative to WinXP or other Windows versions for the home and/or small business user?
Personal opinion here is that if you want something that you can load and pretty much forget about - then stick to Windows. There are versions of Linux - Ubuntu for example - that present a pretty good WinXP-alike desktop, but they still do not have the consistency that Windows has so doing some tasks will require books, forum help etc. I'm thinking especially about hooking up printers.
I would also be interested to know if it could run programs such as MS Office and Adobe Acrobat etc, etc.
Here's the crunch. There are alternatives such as OpenOffice & a PDF viewer, but they are different enough to put some people off. You can also run most Windows software under a Windows emulator but it seems crazy to me to run Linux & a Windows emulator when you can just run Windows.
I guess my summary here is that Windows is still the best option for ease of use & running the common applications. If you're good with computers and don't mind getting your hands a bit dirty then Linux makes sense.
In our family my son runs specialist Geophysics software that runs only in Linux/Unix so he uses a Linux desktop. The rest of us use Word/Excel, Internet & email - and Windows makes more sense for us.
Hope this helps