When I worked in an office most of my clothes were classic, though I generally preferred trouser suits to skirt suits, as I've always been a bit of a tomboy. Anyone who has seen my Winter wardrobe for Project 333 will have noticed that there was one winter dress, two skirts, five pairs of jeans and trousers, plus a trouser suit. Now that I don't work outside my home I have developed a distinctly more casual style, though I do like to wear smart skirts or dresses occasionally. The outfit above is what I wore in Paris when we went out for a meal on my 65th birthday.
The following outfit though is what you are more likely to see me wearing. It underlines the fact that if you had to define my current style using one of those four categories it would be casual.
I've hardly ever worn romantic fashions, as being 5'1" too many ruffles and frills would overwhelm me, plus I'm not really a girly girl. I wouldn't describe myself as a trend-setter either, though if the latest trend is one that I like I may buy into it, in small doses.
It is also worth considering the negative connotations of the four fashion personalities. Classic can easily become boring. Romantic may verge into fussy or dowdy. Trendy is in danger of becoming a fashion victim. As for my casual personality, I must take care that I don't become too sloppy, which is why I aim for casual chic.
I think it can be useful to define your own style and it certainly makes it easier when you go shopping. On the other hand you don't want to get stuck in a style rut. In "Parisian Chic", Inés de la Fressange says that she often dresses in black or navy with a white shirt, but sometimes on a whim she will surprise everyone by wearing a fuchsia pink blouse. For me, it's that surprise element that makes fashion so much fun.