I'd say get one as large as your space can accomodate, and something very sturdy.
I have an old computer desk that I got free from a company DH was working for. They were going to throw it away! It has a thick particle board top, and a steel base that supports the top all the way across so no sagging. It doesn't have drawers, but a shelf at the back that holds all kinds of things and I have my Sterlite drawers up under it. It is 24 X 48" and has served me well for 25 years. Just last month I finally got the nerve to cut an opening and recess my machine, something I've been wanting to do for a LONG time. Check local thrift stores, you can often get a great price on a desk or table that just needs a coat of paint and a little TLC.