BugBear, I have no input on the US Oak but, love your website and thanks for having it out there, it is a great resource and I will build your bow saw one day. And the links to bench pages are a great help, it helped me discover what type of end vise I will build, which is a combo of tail vise and long end vise as one solid unit operated on a double sized sliding frame system with two bench screws.
As far as an opinion on a bench top, I think American Ash would be great as it is not a brittle chippy wood, I have done a little chiseling and sawing of Ash and it has a rubbery tough resistance, as well as being softer than Oak, it will not damage edge tools. Pro baseball bats are made from Ash. On the California coast, $3.95 a B/F.