you can use an existing display or buy an non apple display with a macbook or any mac computer.
No need for a UPS battery back if you have a macbook as well if you where planning on buying one for your mac mini.
300$ bike rack is 6 times more then 50$. the Macbook is not even 2 times the mini in cost.
with a free ipod touch, better resale value , no UPS battery back, one could make an argument that the Macbook total cost of ownership is less.
I was exaggerating with the bike rack comparison of course, because I always hear people trying to minimize price differences by adding a bunch of irrelevant costs. It's not just a Mac thing. And yes you can use an existing display with any mac, but then the price difference is going to be a higher percentage of the combo price....the poster I was responding to was trying to make the case that the difference was insignificant.
If you don't want/need an ipod touch (and that giveaway may not happen anyway) or a UPS (how often are you expecting the power to go out?) then there's no comparison with the prices. Not sure about that resale value either; refurbished 4/2010 MBPs are selling for $300 off in the Mac store while the 6/2010 minis are only selling for $100 off. So you may lose $200 in resale value in a single year by going the MBP route, probably more since you're not offering the buyer a one year warranty like Apple does for the refurbs.