I like ships that are big, the bigger the better, so long as they are not unique/special. Mass produced is good.
For instance, in David Weber's Heir's of Empire trilogy (which is remarkably void of his usual bullshit), they empire's standard warships are called 'planetoids' and are slightly smaller than the moon. The put a couple klicks of rock and dirt on themselves to camouflage themselves. As moons. Those were pretty awesome.
On the other hand, if you blow all your resources on some godawful Terror engine (I'm looking at you, Palpatine), it's not so cool. I like it when not only are they huge and badass, but when there's more of them, either in a huge fleet to begin with, (The Empire Strikes Back has some bitchin' Imperial Fleet scenes), or when, even if you somehow destroy this one, five more will be knocking at your door tomorrow, asking if you know what happened to their friend.
Further, very few things I've ever heard or seen are as satisfying as "All batteries; Open fire."