Some fish get names, but never deliberately... I don't buy a fish and try to think of a name... but sometimes they will just come to me. My first ever "large" fish was a 6" eartheater and we named him Mongo just because he seemed kind of dumb and stubborn, plus he ate rocks. My convict is named Tyrone, my silver Dat is Thurman Merman (we needed a really nerdy name because from the front he looks like a big crosseyed dork), the indo is Nibbler, and somehow a jewel cichlid became Loretta. I think the only one I actually thought about beforehand was naming my baby Arowana Frankenstein. My first instinct on that one was Superfudge but I wanted a more appropriate name for a future monster. I think that aside from a couple of pairs (Mr. and Mrs. Kribensis, Mr. and Mrs. Redhead) those are the only fish we have that are named.
It seems like the ones I (or usually, my girlfriend) put any thought into are the ones that don't stick. They just seem forced.
I think that naming them does create some extra attachment, which really makes it a lot tougher when they die. My old roommate called the largest of our original fish (odessa barbs we got for cycling) Brutus, and even though we had a huge plague of columnaris that wiped out over a dozen barbs, it was only when Brutus died a few months later that we really got sad.
i named alot of my fish when i first started and most of them died so i stopped. my gf has started naming most of the fish in my 55g.
gold sev - shakespeare
green sev - lady
dehlezi - lord voldemort(death eater)
senegal - malfoy(death eater)