IT Work...

You can run Windows 7 on a MacBook Pro just fine. If you already have a MBP, there's no need to buy another computer to run Windows. If you don't have any of them, I personally would still opt for the MBP, so I could run Windows when I have to and Mac OS X when I want. YMMV

 

What IT work exactly? Replacing keyboards or setting up networks for multi-national companies?

 

IT job? They must have tons of laptops there for u to use. Large corporation may even insists u use a company-approved laptop. A back-alley company that's telling you to bring your own laptop...eh... get pay check up front.

 

Buy a Dell through the company's enterprise contact - I have a Lattitude E5420 right now, with Gold tech support and next-day business support. Dell knows how to handle enterprise business support. (Full disclosure - I only do server support, so I never call in for desktop support. But the desktop support team never has anything bad to say about Dell.)

Keep your MBP separate for yourself.

 

Jobs site, definitely something portable, and long lasting batt, no 17" XPS. If maintaining old network equipment would be nice to have an (obsolete) built-in RS232 although a USB-Serial dongle can be used no prob.

In any job, it's always good to "fit in" so if everybody using Dell and you walk in with a Mac, even though boss placed no limitation on you... see where am going with this?

 

I'd recommend Dell, they're enterprise range laptops are rock solid. Built much better than the consumer stuff they churn out. All the Latitude models i've had over they years were built like tanks. You cant go wrong with a Lenovo either.

 

Get a windows laptop and make sure it has an external SATA port.

You may need to debug or flash the firmware on an external hard drive. You need a direct SATA connection for this - doesn't necessarily work over USB.

 

Do not get a mac. As the poster above me stated, you should have an eSata port. Additionally, although I couldn't find any information either way I'm not sure that Windows 7 is certified for the Macbook. Your work laptop running the OS you use for work, should be 100% compatible. Also, Dell business support is amazing.

But those Lenovo's are sexy too.