Orac & CWL,
The MacMini is a great machine, especially for someone in your position with existing keyboard, mouse and external storage.
Regarding Toast, it depends what DVDs you are burning. Remember, burning DVDs with Quicktime is possible with iDVD (iLife is included with every Mac). You can also burn Data DVDs direct from the OS. CWL is right about needing the SuperDrive for burning DVDs.
You could always consider downloading
NeoOffice for free if you don't need all the features of Microsoft Office. It will read and write the Office files as necessary.
Boot Camp needs to be downloaded from Apple's website and the installation notes followed *to the letter*. You burn a CD of drivers for the Windows installation *prior* to installing your own licensed copy of XP. One installed, you can choose to startup in either XP or OSX. Of course, your machine will be as susceptible to virii and worms as any other Windows machine when booted up in XP.
The Duo Core will always be a better investment for the future. However, the Solo Core will run all your Office-type applications, email and web browsing software without any trouble whatsoever.