Take a look at Watership Trading Companine. I have one of these in waxed cotton -
http://watership.imperialheadwear.net/main.php?navarea=Hats&code1=HVN&code=TAX&season=Fall/Winter and couldn't be happier.
It offers great sun protection, high degree of water resistance ( it will last about 60-90 min in a heavy downpour before water starts to permeate), is packable and floats.
I have been tempted to buy a Tilley, but I like just like the look of waxed cotton more.
Good luck.
Billyp