I would say it probably depends on what you're going to do with them..... If someone wants a logo printed (on a shirt, decal, business card etc.) I would suggest a font that's going to be easily embroidered at the same size. We found this out the hard way.....

Again it depends on what you'll do with it, you may be in another whole ballfield.......
That's just my two cents, someone else will probably have a different opinion......
Okay okay I will suggest Arial as #1......

