The primary differences among these distro are their lineage, which several answers have covered. That largely affects how you administer them and the size of their software repositories. Anything based from Debian is going to have a very large collection of software to choose from. All the distros you've listed have plenty of support for developers.
I really agree with John T's remark about OpenSuse - it's not the best choice as a development platform. zillion makes a good point, FreeBSD is 'the' BSD distro. And to expand on matpol's anser: There used to be only 'RedHat'. In 2002 (or so) two forks were created, Fedora and RHEL (RedHat Enterprise Linux. Defora is spnsored by RedHat, but is a community supported distro. From RHEL or Fedora:
A few years ago there was just one Red Hat Linux. As acceptance grew and Linux reached further into enterprise computing, one Red Hat Linux product could no longer be all things to all users. That's why in 2002 Red Hat created Red Hat Enterprise Linux. Stable, supported, certified -- Red Hat Enterprise Linux has become the Linux standard.
The Fedora Project was introduced in late 2003. Built for and with the help of the open source community, the Fedora Project is for developers and high-tech enthusiasts using Linux in non-critical computing environments.
If they all seem pretty much the same to you, it's because they are. They all use very similar linux kernels. They all can run gnome, kde, or openbox desktops. The core software (GNU), which is why purists refer to these systems as Gnu/Linux systems.
When choosing a distro, I typically advise people to pick one they are familiar with - one you can administer with no fuss, after all you want to spend your time working, not figuring out how to get that $#@&&! video driver to work.
If you are new to linux, stick with a stable, popular distro which will provide the most help if you need it. That means Debian, *buntu, Fedora, Slackware, Mandriva or CentOS.
Personally, as my main development box, I would avoid anything that advertises itself on the 'bleeding edge' asuch as ArchLinux, but that is because I am old and get cranky when I perform a routine software update & my video drivers break.