All Linux distros run Linux kernel. There's not too big a different betwen RH, MDK, SuSE, etc. except for those targetted at specific audiences such as server, firewall, etc.
Don't expect the same ease of install/use of Windows from Linux. RH, though, is getting there.
MDK 9.1 install runs an updated disk partition tool that resizes NTFS, for the first time. One could use that tool to resize 2k/xp and install RH next.
I guess you should first examine your goal: do I want to program for Linux or something that is even less popular? If that doesn't work, go to any big job site, search for "linux", "bsd", "unix", etc.