I always thought The Event Horizon looked kinda like a steampunk Klingon Bird of Prey. Not knocking it tho, one of my favourite films
As for Culture ships, pretty sure non-standardisation was the norm
each mind chose its configuration, and with field tech, you could look how you pleased.
The only exception would be warships, while being accomplished at war, the Culture would be at pains to admit it. Hence the brutal class designations given to ships designed purely for that purpose. As a result they are fairly basic, engines, crew modules and weapon pods.
They are judicially re-classed too, after hostilities have ceased, from warship to 'fast picket' or 'Demiliterised ROU' and the like.
The ship's Mind is also encouraged to calm it down, adopting avavtars of a less martial or standard nature (some of them are WAAY cuter too
)