The Strike cruiser has slots for 20x 'infantry' units and 20x 'vehicles' irrespective of their "transport" size - so that could be 20 terminators and 20 Land Raiders (or the 1st company). In addition to this, the spacecraft is assumed to carry 6x Thunderhawks and lots of Landing Craft. This allows the terminators (or other infantry) to be landed in a variety of ways with or without vehicles. The most expensive (financially) would be 5x Landing Craft each containing a Terminator and a Land Raider formation at an army list cost in excess of 5450 points (including the Cruiser) - for a very short game! (You could also get the 6x ThunderHawks for an additional 1200 points, but that is just overkill

)
In reality you have to mix and match the formations and their transport within the constraints of the spacecraft and landing vehicles, and this can make for some agonising decisions on just what to include or exclude for a given mission or playing style (even assuming your pocket stretches to multiple ThunderHawks and Landing Craft).
Finally as others have pointed out, 'empty' THawks are very usefull both for multiple assaults and CAS - but must then be protected from AA which then drags in other elements of the Marine armoury.