In our Mass Effect RPG, the Systems Alliance Battlecruiser Alexandria, SABC-35, is the lead vessel in our frigate flotilla, and it has saved our ship the Gettysburg twice now. The Gettysburg by herself is not a major threat to those damn Batarians, and other nasties in the Terminus Systems, but the Alexandria sure does scare them off.
Cruisers are middle-weight combatants, faster than dreadnoughts, and more heavily-armed than frigates. Cruisers are the standard patrol unit, and often lead frigate flotillas. In the Alliance Navy, cruisers are named after Earth cities (New Delhi, Tokyo). Cruisers normally cannot land on planets, but do possess the ability to land on low-gravity planets.
Original parts from Bagara5000, and the Wolf Shipyard Forums.. Bioware owns Mass Effect, I just practically live there.