Rikki:
Regarding the MacMini -- the info from Apple says you can "use any industry standard monitor, mouse, keyboard". This gives you an enormous world of choices for monitors, for example. Those Apple monitors "recommended" on the site are VERY high end and high tech, and thus very expensive. My advice on monitors: go to a good computer retail store, LOOK at the monitors for a bit, change colors, etc. (or get a demo from sales force). Go back more than once. Find one you really like. Excellent LCD monitors have come WAY down in price in the last 2 years. Samsung, LG, Sony, MAG, others make a number of competitive models.
"Dual core" processors are the latest thing. You should get some more input from a real knowledgeable Apple user (I am not) -- but I suspect that the MacMini would be more than ample for what you want to do. If you decide to use Mac.
The neat thing this year is that finally Apple has a partnership with Intel and a neat new software package that lets you use Apple AND Windows software. Maximum choice. I think it will be a big seller.