I personally LOVE Debian. Debian works nicely and seems stable. I use it to run my servers :) I've never really played a lot with Ubuntu and CentOS, I did however use both (and FreeBSD). However, for school I must use Windows due to Microsoft office (and my hate for anything from Apple since that's expensive).
I have Ubuntu on an external drive so I can boot from when needed. I've only used as of late to exploit a shortcoming in the university network, to avoid installing their garbage antivirus program (TrendMicro). I boot into it once and, since they don't require the use of antivirus on Linux systems, they'll whitelist the PC and allow it network access despite which OS you use thereafter.
I think the most interesting statistic here is that Microsoft went from 97% of all computing devices to 20% since 2000.