... well, as always: it depends. But there has been an interesting contest called Plat_forms back in January with different teams using Java, PHP and Perl to solve a given task in 30 hours. (And if you asking why there were no teams using RoR/Python/.NET the organizer told that there wasn't a sufficient number of sufficiently qualified applications). The detailed report has just been published - go and read it for yourself.
For some fun there's a quiz to guess the technology used by a team just from pictures of the developers.