Hoya. Independent test from Lenstip (best of memory) confirms it to be better than B+W even if the latter is chosen by most photographers (I would like to see some data to support such a claim) as one poster asserts. Go here: http://www.lenstip.com/113.1-article-UV_filters_test.html
I have seen the same tests. I've used both and prefer Hoya, especially the slim Pro line.