As a researcher in the bioinformatic side of Biology/Genetics I suspect it'll be a very long time before they could replace everything I do, as your'd likely need a Strong-AI to do it.

I'm not really a Ubuntu fan, but with the cluster I manage (120 physical cores, 960GB RAM) we've ended up going with Ubuntu 10.04 running Sungrid Engine for a couple of reasons. - The LTS support, by the time the support period ends we should be replacing the hardware any way. - It provides a Grid engine package by default (might not be the latest but it's good enough) for distributing the workloads - A lot of people are already familiar with Ubuntu - Most third party apps provide support for it - It's very stable - It's free Note if your users are heavy R users have a look at installing the Revolution R package from the third party repositories. It can provide some massive speed ups for Matrix work and a number of other jobs.