Over the years, I've used all sorts of desks in my small apartments. I used a nightstand as a work surface in Santa Monica for 2 years, I had a vintage combination dresser / roll-top desk in Manhattan for 2 years, and I made my dining table a full-time work space in my beachside studio for over a year. I currently work from a desk with pull-out extensions on either side, which helps me convert the surface to a buffet when needed.
Below is a round-up of a diverse array of small space friendly work surfaces. (And don't forget that standing desks can be great options for compact rooms as well!)