I use line called Laserpro on my SeaWinds... it's fishing line--I think 80 or 90lb test, and it's braided which gives it an almost scale look to it. I bought it from the Boat Store, which is at the [link=http://www.seawindrc.com]SeaWind Resource Center[/link]. It's probably overkill though, as you're probably not talking about that much force being exerted even in the windiest of conditions. Actually the kit line supplied with the SW isn't too bad, other than it kinks real easy and stays kinked, which I don't like.

Kite stores are a good source for line... or, there's a place called [link=http://www.gbmy.com]Great Basin Model Yachts[/link] out of Salt Lake City that sells all kinds of stuff for RC sailboats--they sell rigging line as well that works well.

Andy
[link=http://www.acmsc.org]Air Capitol Model Sailing Club[/link]