That being said, from a personal experience, nothing increased my development more in the past 10 years than when I switched from a PC to a Mac.
The specific things I noticed were: - Terminal was much more intuitive (as compared to command prompt in windows) - Tabbing between windows on a Mac works much better for me as compared to windows. - It forced me to learn more about how PHP actually works by forcing me to learn more Sys Admin stuff such as file structures, apache configs, vhosts, exim mail configurations, mod rewrites, and proper linking structures. - Right out of the box I could run a full LAMP website on my local box. - It allowed me to become a better programmer by teaching me to extend my application beyond the capabilities of PHP such as executing shell scripts, etc.
I can't stress enough how much of an impact a Macbook Pro had on my productivity and skill development.
http://forums.macrumors.com/archive/index.php/t-202306.html
And the magsafe power adapter can get stuff caught up in it easily, so consider something to guard it (even just a piece of tape might help):