This is a direct answer to your question as to how to make someone choose Mac over a Windows based machine:
1. A Mac works out of the box without the need for too much configuration.
2. A Mac doesn't come with a zillion applications from Sony that you're never going to use.
3. A Mac is not as prone to viruses as Windows based machines.
4. A Mac has a higher resale value. ($1,000 Sony laptop can go down to $500 in just a little under a year, while it'll take about 3 years for an Apple product to depreciate that much)
5. A Mac and OSX were made for each other by the same company therefore almost eliminating compatibility problems between drivers and peripherals. Another up-side to this is that the OSX can maximize the hardware unlike Windows because the OSX architecture was made for the hardware architecture it comes with.
6. OSX doesn't have multiple flavors like Windows (Basic, Premium, Business, etc.).
7. Macs just look so damn awesome.
If those reasons aren't enough, tell him/her to check
http://www.apple.com/getamac
You also asked about the new Unibodies being "stripped down"?
They're not... Before Apple releases a product or even begins to design a product, a thorough analysis of the market is made. What do MacBook users actually use on their machines? What do MacBook Pro users actually use on their machines? What features does the MacBook market really need and want? What about the MacBook Pro users?
There're a zillion questions they ask consumers and test groups before they actually begin developing a new product.
They didn't strip the Unibodies down. They removed the things that their respective markets didn't need or seldom use.
Another reason there're features on an MBP that aren't on an MB is because it stops the products from competing against each other. If an MB came with 2 video cards and Firewire and a better display, that would kill the MBP. They have to separate them by offering better features to their Pro line. They can't cannibalize the MBP for the sake of keeping the low-end user happy. Go pro if you want more than what the MB can offer.