I looooove 1800s/Victorian. Especially the 1880s, there's VERY distinctive clothes, roles, music, morals, etiquette, etc. Plus tons of cultural references you can make -- Gilbert and Sullivan, Jack the Ripper, Oscar Wilde...
Clothes for wealthy women would be hopelessly elabourate, rich-coloured, layered dresses with bustles, ribbons, lace, 'curtain' effects, and firm, low necklines. For upper-class men there would be waistcoats, tailcoats, ruffles, black, white, grey, browns and navy. Oh, and SPATS! (Yeah, I'm into costuming.) For lower-class costumes, look at any Dickens book's illustrations.
The music was getting more adventurous and less deadly serious in the Victorian era -- there were music halls with silly or bawdy songs, and concerts of famous composers of the time, as well as operas and smaller, less-serious operettas.
Manners and appearances were so absurdly important that codes were invented within that system -- for example, google 'fan code', the code of messages a lady could convey by moving her fan in different ways.