I don't think I would need much, but bigger is usually better. Largest draw thing I could think of at the moment is a grinder? But I guess the potential could be there for using it to run some lights and what not for when I eventually get a bed camper...
Edit: this all may or may not be a pipe dream.
I don't think I would want to mess with anything but pure sine because of the potential to fry whatever I may want to plug in. Or am I worrying too much?