Since your code is persistant under mod_perl, you just want to make sure that it's clean code so it isn't necessary to write your stuff in an OO way.
in reply to Re^2: Perl cgi without mod_perl, your experience
in thread Perl cgi without mod_perl, your experience
Really, you want to write clean code - whether or not you're using mod_perl. If it's clean, you'll be able to move to mod_perl later if you want/need/can.
Unfortunately, in my case, I'm re-writing a system I wrote from scratch when I was first picking up the language so it's kind of messy.