If you go the Hoya route, consider getting the Pro version vs the standard filter. The standard version has a really annoying habit of falling apart. They use a pretty flimsy snap ring to hold the thing together and it doesn't like to stay put. You can put it back together just fine but it's a needless hassle.
Since I'm primarily a landscape guy I have a polarizer on more often than off. I use Heliopan and B+W now and am much happier than I was with my Hoya.
[url=http://www.binaryemulsion.com/wordpress]My Photo Blog[/url]