Well, in the past I've dedicated this month to both Evangelion manga and Gundam manga. I might as well keep up this trend and explore some of the other mecha manga out there, starting with a beloved franchise from the olden days.
PATLABOR (Kido Keisatsu Patlabor), by Masami Yuki, based on the series created by HEADGEAR. First published in 1988 and first published in North America in 1998.
PLOT:
In the near future, Tokyo is full of powered robotic suits called "labors." Most of them are used for construction and other forms of industry, but there are those who would use them for crime. To combat this, the Tokyo Police creates a labor force of their own under the guidance of the laid-back Captain Goto. Goto assembles a ragtag crew of cadets to pilot these labors, ranging from the loud, thuggish Isao Ota to abrasive Asuma Shinohara to tiny, eager Noa Izumi. Together they must prove their value to their superiors and the city at large...at least, as soon as they learn to work together.