I'm doing mainly embedded C/C++ development nowadays, but did some Java/J2EE work a couple years back too, and Debian GNU/Linux has been and still is my OS of c

I'm doing mainly embedded C/C++ development nowadays, but did some Java/J2EE work a couple years back too, and Debian GNU/Linux has been and still is my OS of choice, but Ubuntu is probably an easier entry point to the Debian ecosystem. You can easily try it with e.g. Wubi or booting from a USB stick, but if you like it you will get better performance with a native installation. I'm currently running Debian on a Dell M4500 with a first-gen i7 and 8GB RAM, and full HD matte display. It has been an excellent machine for the last couple of years. The current M4700 looks nice too. From 2006 to 2008 I did everything except development (only some web dev stuff) on an Apple Macbook. It was a really good product, excellent font rendering at the time, stuff just worked. Well there was some pain with using fink/darwinports and rails etc. back in the day, but I think that is a solved problem today with Homebrew. During 2011 I also had a contract where I did C# development in Windows 7 on a high-end Dell Inspiron with an i5 and 8GB RAM and a 160 GB Intel SSD. This worked fine too even though Visual Studio was still slow on our rather big project. For a general purpose development machine today I'd look at lots of RAM, i.e. at least 8GB, at least a good i5 cpu, and an excellent screen with at least 1920x1080 and I prefer matte displays for development. Good full-size keyboard too. SSD is nice too, but at least on Dells it probably cheaper to replace the disk yourself. If a laptop, some people like to have a docking station that is able to drive two external displays. I don't, mainly because my M4500 display is so much better than the glossy cheap external displays I have access to at work. If you can afford it the 15" Macbook Pro with a Retina display is pretty sweet. Having used Linux+Mac+Windows the last couple of years has given me the knowledge to be able to get work done on all of these platforms, and debunk FUD about why a specific plaform sucks/rules. I think that is an argument to switch platform every now and then.