The Tank is clearly the coolest kind of ground fighting vehicle. A steed for modern day cavalrymen. Fast moving, heavily armored and with gun that can blow holes in anything it can see.
The role of cavalry in modern warfare remains to add tone to what would otherwise be an unseemly brawl.
Years of experimentation have found the purest form of the tank.
It is low and wide. It has ONE turret more or less in the middle. It is armed with ONE main weapon - a long barreled direct fire cannon. The driver sits in the middle at the front. The vehicle has no windows other than small vision blocks.
It has tracks, not wheels.
What does this mean?
For the sci-fi artist, what this means is that if you are drawing a tall and narrow wheeled vehicle with three turrets, each with two stubby guns and a missile rack where the crew are clearly visible behind big panes of glass you are doing it wrong.
This is a faux pas on the scale of drawing a two man fighter spacecraft where the crew sit next to each other rather than one in front and one behind!
It is acceptable to replace the tracks with grav units or thrust fans, so long as these do not alter the profile too much.