Go to Dell and price a comparable laptop meaning a Precision laptop and spec them out the same and see the prices then. All the laptops at $499+ all look good on paper.
Look at the ultrabooks coming out now to compete with the Macbook Air......they are having a hard time getting the price under $1000 because of quality components and not junk.
And as always with Apple they usually only update once a year, maybe twice with the laptops, but its usually best to wait for the next update to get the latest and greatest. Sometimes Dell/others get the products out quicker that have been updated over the year, but usually Apple will update pretty quick on a new release of hardware like the upcoming ivy bridge.
Plus with a Mac you have less problems with hardware in my experience over 11 years, plus you can run OS X, Windows, Linux, etc. I only run OS X, its nice not having to worry about spyware, etc and things always just work usually.
Every time I turn my Windows 7 PC on I am troubleshooting or updating or wasting time in one way or another.