Mary-You do make a really good point. I'm leaning toward a white oak or Isu. Do you remember were you got yours from? Thanks.
Argh, wish I could help! It was part of a bunch of weapons my then-sensei ordered from Japan. He has since moved on to the West Coast, alas (this was a few years back). Others will have more recent purchasing experience that's definitely more relevant here. Obviously I don't have experience with lots of different kinds of wood -- all I can tell you is that Japanese white oak is tough and resilient and a great wood for a bokken that gets plenty of real use.
Also, if you don't have a weapons bag yet, you might want to see what happens when Bujin rises from the ashes. They were for many years a most respected supplier of gear, went out of business fairly recently (about a year ago) and rumor has it they are coming back in some form. If so, you may want to save your money for a Bujin weapons bag. Mine has been dragged from dojo to dojo for years, and...wow. See, now you've got me getting all sentimental about my weapons and my bag. Well, there are a lotta good memories there, and it really be the last weapons bag you'll ever buy.