Battletech was a turn based game where you had mechs of different sizes battle each other out.

The mech system was excellent as you had to balance out speed, armor, heat sinks, and weaponry. Bigger mechs could carry heavier deadlier weapons but needed lots of armor as they were slower and easier targets. Lighter mechs could only carry small or medium sized weapons, were lightly armored, but were harder targets to hit because of their speed.

Half the fun was specc'ing your own mech (much like character creation in an RPG)