Flavor of Linux is inconsequential to learning Perl. So long as it is Perl5 you should be good to go. That said, my favorite flavor of the week is Linux Mint. I like the fact that things just work under Mint. Mint is a Debian descendant like Ubuntu is. If I had my personal laptop handy I'd tell you the version running on it, but on my desktop which runs straight up Debian runs 5.10.1 Perl. My laptop runs a much newer version of Mint so I cannot imagine the Perl is going to be of an earlier version.
My laptop is Minty Fresh! :-)
Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg