I've had the Tova Top on my list of to do's for about a year now, and I've been considering what fabrics to use just like you. One thing I did early on was browse through Wiksten's Flickr pool (
http://www.flickr.com/groups/wikstenpatterns/) or just do a "Tova Top" photo search on Flickr and look at what kinds of fabrics others used. See what you think drapes nice and looks best. If you see one you think looks good, click on the photo, sometimes the seamstress will say what fabric she used. After doing that, I decided that I liked the way chambrays look, linen blends, lawns, and double gauzes look, but that's my personal preference.
Also, the season you plan on wearing your top could determine the fabric you choose. For example, a thin lawn or cotton might work best in the spring/summer; a thicker chambray or linen might be better in the fall/winter. I've also seen some people shorten the sleeves for warmer weather wear. I've also seen it layered with a long sleeve knit shirt under for cold weather. Just some food for thought.
