As a Linux fanboy, I held out against purchasing a new Mac for quite a while. I finally bit the bullet, however, and picked up the new Macbook after pouring several cups of coffee into my previous laptop (which was running CrunchBang and Linux Mint). It was one of the best purchases I've made in a long time.
I'm using the Macbook for coding in Java and Python, and plan on installing the next version of Flex Builder when Adobe releases it (I've been doing Flex development on my Linux PC for the past 8 months). I'm also learning the Cocao framework and the XCode IDE for developing Mac apps (just for fun). The tools I use to develop (Eclipse, Emacs, Vim, to name a few) were either included or easy to install, and I haven't had any problems with day-to-day coding. I'm also running CruchBang Linux in VirtualBox on the laptop, so I have a Linux distro immediately at hand.
I would highly recommend making the switch, if you are ready for a new system.