First, the configuration most comparable to a 17" MBP is $2,069. You need to add the 1920x1080 display, the 2.8GHz CPU, and Bluetooth. So your "$1000" MBP price difference is actually more like $700.
Second, the MBP has several hardware advantages:
1. a superior video card, along with the ability to run on integrated graphics to save power
2. a FW800 port
3. more than twice the battery life
4. a larger, 17" 1920x1200 (16:10) screen, rather than the 16" 1920x1080 (16:9) of the Dell
5. the ability to drive a 2560x1600 external monitor
6. a slight weight edge, despite the larger screen and better battery
7. much thinner
The Dell's design is horrible. Any laptop with both leather (!) and a gaudy silver racing stripe is not something I want to be seen in public with.
And, of course, there is the OS X vs. Windows difference. At this point, I mildly prefer OS X itself, but I *vastly* prefer OS X applications. Generally speaking, OS X developers pay much more attention to detail than those on Windows.
For me, given all of the above, the extra $700 is a no-brainer.
And Sesshi: You've still never explained, after all this time, why it is that you think Mac laptops are support nightmares. Their failure rates are comparable with those of the rest of the industry.