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...that makes the Mac look even better. If you add some of features you find on your "low end" Mac Mini, like Firewire, Bluetooth and Airport, then I think you'll find the Mac actually is cheaper, esp. when you now consider how much they've upped the RAM more recently. hard-drive sizes are still smaller.
Mac's are cheaper when you compare on a feature by feature basis. It's just that most neglect to do this. This is particularly evident on the Mac Pro line where in a feature-for-feature comparison Macs are sometime thousands of dollars cheaper than their PeeCee counterparts. There are some excellent articles on this on Macworld and other places.