Bonus points if the author first mentions a specific trait, physical build, or whatever else halfway through the novel and totally fucks up my mental image.
I don't expect a biology model description for each character, but write me something brief and evocative of how they should look, you fucking dork author. I don't even know how tall she should be, her hair colour, anything. Why are you like this, author?
I'm pretty sure older works were very heavy on physical descriptions. And then moving pictures came around, and readers didn't care as much about visual characteristics as they did the plot.
If you read Victorian era stuff, FFS they don't stop describing how things look.
Por que no los dos?
Older text was more visually descriptive. Dunno what else you'd like, comrade.
"What I'd like" is probably not good and kinda scary =)