I've seen this question many times but the answer is always "uncheck the IME from the 'Language & Keyboard Settings' menu. The problem is that there's NO checkbox there.
Menu - Custom Locale - en_US is selected.
Menu - Settings - Language & Keyboard - Select Language - 'English (United States)' is selected.
Menu - Settings - Language & Keyboard - Japanese IME is the only IME and there is no check box to remove it.
I've also put a cursor into an editview and tried messing with the keyboard options visible while typing. How the heck do I get English to show up? This used to work fine before an unfortunate reinstall.
Long press a Text Field > Input Method > Android Keyboard