Computers

"a computers do not do what you want it to do, but what you tell it to do" -- Someone

The language does not matter...

but the libraries does. this does not seem so controversial, until you look at what the trolls and dogs say about the languages:
"[java/python/c/c++/C#] sucks b/c [x,y,z] and thereby [java/python/c/c++/C#] is better then [java/python/c/c++/C#]"
We have all seen it an Identi.ca, status.net, twiittard and 4chan. this was my possision on java, I hated java, and loved C and C#, then I saw Minecraft.... It changed my point of view, it is realy not the language that is the problem, but programmers, some languages fit some programers better then others, dynamic languages like Python is fun to program with, and Java is better at being cross-platform then C.
The fact that Minecraft is as fast at it is is remarkable, considering it has to calculate what blocs to show and at the same time generate thousands of blocks in seconds. The logic is just remarkable and shows the that is is not the language that is the problem, but the programmer. Java has not sucked in several years, it now has JIT which is/was one of the selling points of C#/Mono (Monos jit is faster then the Microsoft jit implementation*).
Now even C can be compiled into code that is run in a jit (LLMV and CLang). and the once slow language Python has its own jit**, which is fast as fuck***.

Toolkits does not matter...
I am a GTK fan boy, and I hate Qt.... well maybe not, some of my favourite apps are written in Qt: mumble-client and bzr explorer. but there do not integrate well in to the desktop environment that I use (Gnome). but truly the problem here is not that Qt is bad but that GTK looks better on my desktop.

The DVCS/DRCS does not matter....
.... as long as I can use bzr to get your git.
I do follow some projects that are using git on bzr, but some projects are just retarded and are dependent on some aspect of using git to even compile****, whish is a relay bad decision making imho. when writing code and using DVCSs, do not make it unmigrational, or that it can not be pulled in other ways then via your DVCS, be it curl, git-bzr or bzr-git*****.
I must say that the backend should not matter here, only that you can make patches and run the code without using tools you do not want to use.
I like bzr b/c its integration into Nautilus and hate git b/c of its way of naming revisions and file handling. That is why I want to get your git with my bzr pull.

* http://geekswithblogs.net/ciscbrain/articles/Mono_vs_dotNet_Performance_Test.aspx
** http://psyco.sourceforge.net/
*** http://blog.dhananjaynene.com/2008/07/performance-comparison-c-java-python-ruby-jython-jruby-groovy/
**** http://dev.xonotic.org/projects/xonotic/wiki/Repository_Access (the ./all script uses git to pull the sub directories and has to use git to even compile)
***** http://doc.bazaar.canonical.com/migration/en/foreign/bzr-on-git-projects.html and https://github.com/pieter/git-bzr