RedHat here. ;D But I have nothing against the other distro's. When I upgrade my connection to DSL I will probably be buring cd's all the distro's. ;D
I used debian, when the kernel version was still 1.x. It was the first distro I ever installed.
Turbolinux 4.0, Corel, and Caldera 2.3 I have also installed and played with before from cd's I got at comdex.