Well, that assumes that there is the opportunity to choose. Our university has a standard Windows and UNIX workplace, and that's what you get. I am not complaining, because it is actually useful to have the same environment everywhere, and a recent Ubuntu version is used for the workplace (and Debian on servers). Fortunately they have banned old (but supported) Red Hat and SUSE versions.
However some computing resources with a lot of cycles use old RHEL/CentOS/Scientific Linux versions, e.g. one particular cluster has just migrated from RHEL4 to RHEL5 (which is not really stellar). Compiling our codebase there is always a drag, where you have to bring things four or five years back in time.