As a practical girl, I would also look at whether or not this room would be considered a bedroom, office, etc for a future resell. Besides nixing the carpet idea, which you already know, if you have the funds, go hardwood floor. It is a long tern purchase but any future buyer would want hardwood over tile. Hardwood also will stand up to the wear and tear of a sewing room and be refurbish-able for any future use. Hardwood flooring really cuts down on allergies, comes prefinished now and easily cleans with a vinegar/water mixture. I use a microfiber rag dipped in a vinegar/water solution and wring it out until almost dry, and run it across my floor. There are also roller wheels for chairs and furniture that are meant for use on wood surfaces.
If you are in a basement, then tile would be great. You will have lots of choices. post a pic when you're finished!