My military preference is for a cavalry heavy army with fewer infantry and a mixed archery unit.
For the cavalry, I tend to favor Ravenstern Mounted Rangers, Men-at-Arms, and whatever adventurers, rogue knights, and other mounted units I happen upon.
For my infantry, I play pure defense- anyone with a shield who knows how to use it. A handful of Legionnaires and Armored Axemen may get stomped down by a cavalry charge, but they'll get right back up. Occasionally, I will mix the heavier, non-lance using mounted units (such as adventurers) into their ranks to compensate for numbers or for special encounters like the Jatu. Cavalry walls are good at slowing charges and allow the footmen to pull the riders down.
The game settled my ranged issues for me. By default, Vanskerries are counted as "archery" units, what with their throwing axes, but they also make handy melee troops. By adding a few less Ravenstern Rangers to the equation, I feel that I've adequately balanced my army's defense and offense and effectively screwed many an enemy flanking maneuver.
The end result is a compact (albeit, slow-moving) company that excels at range while still being extremely effective in close-quarters. Meanwhile, I ride about with a couple of bodyguards, drawing off enemy heavy cavalry units and cutting down their horses before returning to the fray to flank the enemy's archers/traffic-jammed light cavalry.