If you are definitely running Debian on your potential MacBook Pro purchase, have you researched to see whether there are drivers available for all of the features offered by the MacBook Pro?
Looking at Debian's
Wiki page, there seems to be a few potential issues and the page does not seem to cover the unibody MacBook variant much. It doesn't state whether the ambient light sensors for both screen and keyboard as well as trackpad gestures work accordingly to how they work in Mac OS X. Since the Wiki page is quite long, I would imagine there are other small touches offered by the MacBook Pro that could be an issue too in Debian.
In fact, are you actually going to give Mac OS X a try other than using it to help install Debian?
If not, how are you going to update the following components' firmwares if you're going to use Debian solely:
- EFI
- Trackpad
- Keyboard
- Hard drive
- Graphics
- Bluetooth
- SuperDrive (CD/DVD drive)
The above components have been updated previously and what if you get an iPhone or if you already own one, how to you going to update its firmware, sync its apps as well as backing it up?
Would you rather follow all the instructions on the Debian's Wiki page just to get Debian barely working if I'm not mistaken?
Whilst using Mac OS X, you already have it fully working out of the box without having to spend hours if not days trying to get it to get something to work in Debian (depending on your experience) and potentially still have some left over problems that may not even have a solution for a quite a while!
Mac OS X may have a UNIX foundation but that doesn't mean it makes installing Linux distros easier since again, the MacBook Pro has lots of small touches that are not offered on other laptops. These other laptops are more likely to be supported better by Debian and other Linux distros.
To summarise this post:
If you want an infinite amount of fully working customisations, the MacBook Pro and Mac OS X is definitely not for you.
If you want a fully supported, streamlined and easy experience, the MacBook Pro and Mac OS X is definitely for you.