The professional goes by many names.
The UxP Label Grab Bag
GUI Designer
Information Architect
Usability Engineer
Interaction Designer
Graphic Artist
Visual Designer
Usability Analyst
Interaction Architect
Content Integrator
Data Modeler
HCI (Human-Computer
Interaction) Specialist
Documentation Writer
GUI Web Specialist
Online Help Designer
Help Systems Analyst
Content Manager
Usability Specialist
UI Engineer
Front-end Designer
Customer Experience Design
Business Design Analyst
Conceptual Designer
Requirements Analyst
User Centered Design
Interface Architect
Take a look at this long list of UxP Job Titles:
(I've answered to most of these over the course of my career.)
This whole UxP thing has emerged only relatively recently. The role itself is an integrative one that encompasses several major organizational silos.
Just Call Me "Slash"
The UxP professional is a designer / architect / librarian / documentor / psychologist / artist / technician / counselor / etcetera polymorph who wears many hats.
So it's not terribly surprising to find that "the UI guy" goes by many different names, depending on who's defining the project space:
Technical
Business
Marketing
Creative
Documentation