[nightfighter]

Berber carpet. Could also put down sleepers, foamboard insullation and plywood subfloor before berber carpet.... Less expensive than wood flooring and easier/cheaper to clean or replace IF you ever get water.
I would also look into remnants at the carpet stores. Can have them sized and bound. Add a lot to give more finished feeling over a bare or epoxied concrete floor. Finish of walls and ceiling (ie lighting) are going to have a major effect on the finished feeling. Insullate/soundproof the ceiling if possible.