You care about specs, she cares about everything else.
When I went from a windows laptop to a Macbook, here were the differences:
1. Trackpad was miles better. Smoother to use, easy to click, bigger real-estate, tap-to-click, and gestures were all huge improvements.
2. Screen quality was much better.
3. Keyboard was much better. The material felt better and was easier to type on, and the keyboard even lights up in the dark.
4. Magsafe connector was amazing. No more tripping over wires. Not having a huge power brick in the middle of the cord was also a great improvement.
5. Form factor. I still haven't seen any consumer notebooks as thin and light as the Macbook Air. Easy to carry, and feels great in your hands. This is huge for a laptop.
6. Battery life. When I went from a windows laptop to a Macbook Pro, my battery life went from about 2 hours to 6-7 hours. It was actually a laptop I can carry around all day, not something I have to plug in all the time.
7. The OS. No bloatware, no setup required. You can still tinker with settings all you want but for the casual user, you don't really even need to touch preferences.
7b. The OS design is friendlier. Large bright icons make applications easy to find, and the search is much more functional compared to Windows search.
8. Build quality and future-proofing. My Dell laptop was flimsy, scratched up, and extremely slow after 2 years of use. Battery life went down to 30 minutes and sometimes wouldn't start unless I plug it in. My Macbook Pro (from 2009) is still very usable, looks close to new, and retained most of its battery life. It also has a higher resale value.
Now let's look at your arguments for a windows laptop:
1. It has better specs.
Unless you're doing serious video-editing or running the latest PC games, that doesn't even matter. Yeah I'll pay $300 extra to get all of the above.