Punisher War Zone Vol 1 issues 1 to 6 by Chuck Dixon and Jr Jr.
I loved issue 6. Wall to wall carnage and mayhem.
I loved the iced lolly torture scene!
Warzone 1-6 definately makes it into my top five story arcs. Circle of Blood would be there, as would Suicide Run, Welcome Back Frank, and I expect at least one of Ennis MAX story arcs - either Black is White/Up is Down, Mother Russia or The Slavers.
For single issue I thought that 'Do not Fall in New York City' from the MK run was excellent.