I agree the band system in bk2 is the easiest, however I dislike the computer rules in BK 2 (feels like trying to run a starship using a pocket calculator)...I usually use the Bk 5 rules for simple RP starship combats, but "soften" the crew hits (roleplay the explosive decompressions, etc to see who lives rather than 100% fatalities - makes people think about where they want to spend combat!). IIRC, bk5 assumes a "skill level" of 2, so depending on character skill I adjust the final to-hit. Be warned, this can result in a lot of "no hits possible" and even some "no misses possible" results (if computer levels are far apart and target agility is high). I also like how it incorporates more player skills into combat (pilot, fleet tac, ship tac) although this is not so important for CT...but pilot adds (skill-1)/2 to ship agility. And it has bigger, more advanced weapon choices...
for big ships (cruisers and up) I like Power Projection: Fleet (although it may be out-of-print these days). Has a nice "star fleet battles" damage resolution feel, with non of the complicated rules. This is a pseudo-vector based system that is very easy to learn. Most battles are over in less than 1 hour, 2 for big fleets. But unless everyone has their own ship, it can be boring for some.
One can also do a pseudo-power projection fleet game by adopting the book 2 rules (number of "hits" on the bk2 drive chart equals number of "hits" on the PPF ship ssd, etc). Changes to the total hits must be made (I think I used 10x) This takes more prep time for the ref, but results in a quick and easy combat system. But unless the gaming is 1-on-1, it can be boring for the non-crew.