Most Linux distros will work with Parallels. I use SuSE and have also tried Debian and Ubuntu. Getting the resolution to the native notebook resolution was a pain in Ubuntu for reasons I can't fathom, but was fine in the other distros.
As someone said, there is no need to use Bootcamp because most Linux distros will partition things themselves, BUT if you're under Apple Care or Warranty, you should use Parallels, VM Fusion or Bootcamp, because otherwise if your HDD craps out, you might not get helped.