This can be a potentially trollish question…
Everyone will defend *his* distribution tooth and nail.
The one recognized as the most stable is Debian, it is the one used for many servers.
Its disadvantage is that it evolves slowly because the quality controls, the respect of the free licenses is constraining. For companies this is not serious, on the contrary, especially since vulnerability corrections are very well monitored.
It is 100% non-commercial
Those who want less inertia at home will choose Ubuntu which is based on the Debian package system but has a faster evolution. It is based on a commercial company. It is used in companies for workstations.
RedHat is the distribution most used by companies across the Atlantic. It has a free version called Fedora. Its interest and its economic model is the power of its service. It is used in both server and workstation versions in companies (these are different versions of the distribution).
I use Debian as a matter of principle: it is the only one that is entirely free, that does not depend on any commercial company and that relies only on free licenses.
I wouldn’t presume to say it’s the best, though.
I was asking myself exactly the same question when I started using Linux.
First of all, there is no real ‘best distro for a dev’… Just because a developer can do many different things. A web developer is going to want an OS that supports a maximum of different browsers and flash/silverlight. A game developer is going to want to run them (so at least be able to run wine cleanly from his distribution). A network administrator, a physicist developer or others will want even more features. So it totally depends on the person.
On the whole Linux is the right choice for a developer. The rest is more personal preference.
I tried Ubuntu, Kubuntu but I had trouble with a lot of things (and, yes, the look and feel was part of it).
And finally, when you’re “new” to Linux, you want an environment that you can easily get used to, and where you can install your usual software easily… If possible, it should also be stable, and it should look a bit like Windows or Mac, at least in the UX.
Linux Mint meets almost all these criteria and has a very active community. So I gave it a try, and I’ve kept it ever since. I’m not saying it’s the best distro, but it’s pretty nice, I managed to install everything without breaking my teeth (except silverlight…) and I was able to customize it to my liking (among other things, the use of a terminal with columns and the terminal font of MacOS, because I find it relaxing!)
It may not be the best linux distribution, but I think it’s clearly a not too frustrating solution to start with!
Fedora because this distribution has the most recent packages. So you can enjoy all the features. Fedora is one of the most thins to develop on linux.
I am very doubtful about the answers to this question. They seem very arrogant. Yet Ubuntu is not made for dev.
It’s like “which car should I buy?”, when they are all combustion engine cars, or diesel models (as with Linux, which is only the kernel, not what is around), or even VAG derivatives: the Golf, Audi A3, Skoda and Seat are from the same company, same technical platform: your choice will be according to your tastes and means (skills), the options too (pre-installed and parameterized software)
Have fun playing with a pretty fast because light but already very very complete: “toutou linux”, Frenchized, very easy.
At the other end, even more complete than Ubuntu, “Mint” even adds non-free software (drivers for your graphic cards or wifi a bit too proprietary… and other codecs too), just as easy.
Between these two extremes, in fact, play with testing various often, and as such, have fun with a bootable USB key thanks to the LinuxLive USB Creator software
the most brilliant software I’ve found in 20 years, ultra easy and pleasant to make bootable Linux keys!
In general, I would say arch coupled with i3. Either the distribution is not so important? But arch offers an easy to use modification level for a beginner (compared to gentoo). I3 is the best window manager for developers. It is rather quick to learn even if difficult at the beginning. It allows to develop in the best conditions.