When I arrived, the Hilton in Osaka was offering roughly 75 Yen for $1 USD (TC) and slightly less for cash. When I left 8 days later, the Hilton in Tokyo was offering 72 Yen for $1 USD (TC) and 70 Yen for $1 USD (cash).

I went to 7-11 ATMs twice. Chase Premier checking accounts allow you 4 non-Chase ATMs per statement period without paying the Chase fees. From what I can see on my statement, it looks like there was a $3.90 fee (exchange rate adjustment) charged for every 10,000 yen.
11/16/11: 30,000 Yen = $401.61
11/23/11: 10,000 Yen = $134.02

My CC charged 2.5% foreign transaction fees on all my purchases even though they claimed there was no charge when I called before my trip. If you are used to living in the US, please be warned that many places in Japan do not accept CC. You will need to carry JPY.