From what I've been reading, most knitters have a spot in a corner with a chair or a place on the couch where they sit and knit. The questions of the day is: Are you comfortable?
Does whatever you're sitting in give you enough support? Is there an ottoman or stool you can use to put your feet up on? Would the addition of a pillow behind your back or on the footrest make you more comfortable? A plain-colored lap blanket can help you keep warm and also make it easier to see what you're knitting - when you look down at your knitting, it should stand out from a plain background (don't use a dark lap blanket and knit something black!).
What about your lighting. Is the light strong enough and 'daylight' adjusted? The reason Ott lights are so good is because they give a full-spectrum light and clarifies and illuminates without glare or color distortion. The Reveal lightbulbs also work quite well. Make sure the lamp is positioned so that the light falls on your work, not in your eyes of on the arm of the couch. I recently realized that when I knit lace and used my Ott light, I made fewer errors (you know, the missed yarn-overs, or miscounted stitches...). Just being able to see my work more clearly make a huge difference.
It is nice to have a table or, set of shelves nearby on which or in which you can store a few necessary supplies for whatever you're working on. And you also have a place to put the mandatory liquid refreshment and chocolate.
Knitting should be a relaxing experience, and the more comfortable you are, the more relaxing it should be, so make your knitting space as welcoming as possible.