[Mobhack]

80x80 is what I tend to use for a leg infantry battalion sized force's campaign maps. For mech and armour, I stick with the default 100 wide by 80 to 100 tall.

40-60 tall, and 80 deep would do for a company of leg grunts in a campaign. you might concentrate yourself on a 20 hex wide corridor somewhere in the middle of that, but then you have flanks to cover - which is always more interesting, IMHO.

As you get 750 support points in a meeter, you'll have enough for a second support leg coy and some tanks too (if you use the buy points - remember that's not compulsory).

80 deep is enough to walk across in 25 or so turns, and leaves room for rear area troops like arty and mortars without these being too close that they get shot up by enemy direct fire weapons on open maps in decent visibility. Or overrun by tanks in turn 4 or so, if you left them unscreened.