This is not easy for me to do, after the first 4 (which are easy choices) but my top 10 series would go something like this (the order is interchangeable!):
STARMAN by James Robinson
JSA (and JUSTICE SOCIETY OF AMERICA but I found his 81 issues of JSA better) by Geoff Johns
MANHUNTER by Marc Andreyko
FLASH by Geoff Johns
JLA by Mark Waid
JLA by Joe Kelly (if we're inclusing minis JUSTICE LEAGUE ELITE would be a contender to)
INFINITY INC by Roy Thomas (this definitely isn't in order because that should be somewhere in the top 5!)
GOTHAM CENTRAL by Rucka
YOUNG JUSTICE by Peter David
WONDER WOMAN by Greg Rucka (both stints but his pre REBIRTH/New 52 stint was probably stronger).