I'll somewhat echo CW's comment:
I prefer for all my forces to be generally based around having two armor platoons, two mech-inf platoons, and either a platoon or section of the following--scout/recon vehicles, VTOLs, headquarters elements, fire-support, and CAS.
In actual models that equates to:
o 2x(3-5) Tank equivalents
o 2x(3-5) APC/IFV equivalents, each with a squad of rifleman or specialist teams as desired
o 1x(3-6) Recce equivalents
o 1x(2-3) HQ equivalents (from Tanks to IFVs to Jeeps)
o 1x(2-4) VTOL equivalents
o 1x(1-2) CAS aircraft (optional, but they make a nice impact on the table)
o 1x(2-4) Mortar carrier equivalents
o 1x(3-6) Artillery carrier equivalents (optional since they may be off-board but they help in special scenarios)
o 1x(3-6) Cargo/LogPac equivalents (also optional since they may be off-board but they help in special scenarios)
o 1x(2-3) Specialist Vehicle equivalents (again optional since they may be off-board but they help in special scenarios--think CEVs, radar vehicles, etc. here)
Of course, a particular force you are putting together can depart to illustrate doctrinal, technical, or aesthetic differences. While these may seem big, they can allow players and game-organizers the latitude in putting armor- or infantry-heavy company teams on the board or allow for a fairly big company-plus team. They also allow for a departure from the standard meeting battle. You can do convoy protection/security scenarios or protect a firebase, for instance. Alternatively, you can paint some of the soft-skin vehicles in a neutral color and use them for one side or the other as the scenario dictates.
If you want to expand, you can delineate how big a company formation is and double in in armor and infantry assets allowing you to put a battalion-minus (two companies) in the field. Say, three platoons each armor and infantry for a triangular military which could also allow you to field a pure armor or infantry company…
Hope all that helps!