I admit, I like trench coats. They are convenient one-piece weather protection plus they can hide a bunch of pockets. Above all, though, they can swoosh dramatically.
I don't generally think of myself as a foppish dresser but I do like the way a trench coat can spread out when one is striding purposefully towards an important meeting. I think The Matrix was probably the heyday of dramatic trenchcoats, albeit ones with gathered waists. (Anyone else notice that Neo's trenchcoat is based on a traditional woman's coat pattern?) Dramatic garments then got downgraded again with The Incredibles. ("No capes!") Personally, I always think back to earlier references: those scenes where Sherlock Holmes (the Jeremy Brett incarnation, of course) would grab his top hat and coat and bolt out into the thick, industrial-grade London fog, chasing after a nefarious criminal.
I'd consider a layered Victorian frock coat if that was still socially feasible. Instead, a trench coat works wonders. One can stride in such outerwear. Striding in a windbreaker isn't the same. An anorak lacks potential. Pea coats are too dull and leaden. Snow jackets leave one feeling hollow. Slickers? Don't get me started!
Today's random screed courtesy of the lack of morning caffeine. "Caffeine: OMG! Bounce!" Brought to you by the Caffeine Council of Excitable People.