So here I give my subjective answer.
From my experience everything related to statistics is best solved with R. I have seen this often that in fields related to statistics, R has the most libraries and very often the most state-of-the-art algorithms/methods implemented.
Most programmers like me like to stay with the languages that they know, and learning something new is a trade off, mainly because it's time consuming.
So if learning a new language is a viable option, R is a good choice, in my opinion the best.
Take a brief look at the R libraries related to Bayesian Networks and Bayesian Interference.
Baysian:
http://cran.r-project.org/web/views/Bayesian.html
Graphical Models:
http://cran.r-project.org/web/views/gR.html
Machine Learning:
http://cran.r-project.org/web/views/MachineLearning.html
The main advantages of R:
- easy to install a library: install.packages("RWeka")
- the help format and style is the same for all libraries
- if you know R, it's easy to switch from one library to the next. So it's easy to test all available libraries and then use the one that fits best