Obama's speeches and inflections seem to be from another era. This is one of the best political speeches I've heard in a long time (and I use the word "heard" loosely -- people living in Oklahoma don't matter in national elections, thanks to the electoral college and all that):
In his speeches, Obama seems to be going for the FDR style. Not a bad role model --- FDR changed the whole paradigm of how politics works in this nation. His New Deal was followed by four decades of prosperity. The American century was American in large part because of FDR.
Just because Obama talks like FDR doesn't mean he's going to be as effective as FDR, of course. He is wrong on some issues (for example, universal health care is impossible without mandates), but he's still the best choice on offer in 2008.