Don't forget the box of quadrants, RndrSafe, or changing winter air for summer air in tires, and as I mentioned elsewhere, the cannon report.
My fav would be the Crusader if it was ever deployed, of those artillery pieces that I've worked with I've found the M109 series superior to the M110 series, Gunner - despite it's smaller projo. For that matter I've kicked the most rounds into the air with the M102 105 mm.
For non-artillery pieces, I liked the gamma goat (yer a REAL old timer if you remember that beastie). Was wicked fun to drive.