these three vessels became the backbone of my fleet; With 3 engined planetary strikeships developed, it became more important to have ships that could move quickly than hold a line; Being a technologist, we usually had the upper hand as far as weapons technology was concerned anyway.
The Hunter, Fleet Interceptor; either working in squadrons of 4 or a squadron attached to a cruiser.
The Lorathi class Destroyer, backbone of the fleet. They work in pairs.
The Panther, pride of the fleet and for a very long time the largest ship in service. Never without a full escort.
Though there is a small hull corvette, the Puma and Caracal, these and the slow line ships (the Lion, Tiger and Kilrathi class ships, and Starfighter class Interceptor) are not nearly as common, given that effective use of planetary strikeships dictate speedier vessels. The Caracal Scout variant did prove useful (as it was the fastest ship in the fleet at the time of the only shooting war i've had in the last game) as a rear-area resourse and constructor raider.