I'm always happy when novelists can use something other than beverage preference in order to set their characters apart. For instance, when I read that a certain character just love espresso, fine, they love espresso. If they love beer, fine. But what would be more revealing? For me, I like to know what kind of writing utensils a person prefers--mini-pencils, 12-to-a-pack Bics, Bakelites, or what? I usually keep pens in bulk, as they're constantly migrating away from me. Pens and hair ties I would never be able to collect because I lose them in such mass quantities.
I know some people who are more protective of their pens than their pin numbers. You might be granted permission to use said pen, but if it isn't back in its spot, you're going to hear about it. For me, I like Bic Fine Rollers, or really any pen that boasts slightly viscous ink. I like the kind of ink that will start bleeding if you stop writing. I can't stand barely-there ink, or pens that make writing feel like engraving wood. If you're between pens, the Fountain Pen Network has a list of reviews. Until I can track down a Stylographic (Mark Twain obsessed over this one for a bit) I'm going to start pre-gaming for the next Los Angeles Pen Show.