Starting with 1960:
1960: Kennedy
1964: Johnson
1968: ?
1972: Nixon
1976: ?
1980: ?
1984: Reagan
1988: Bush
1992: Clinton
1996: Clinton
2000: Gore
2004: Kerry
2008: Obama
2012: Romney (so far)
How on earth did the media ever favor Nixon or not favor Obama?
My list, starting with 1960:
1960: Kennedy
1964: Johnson (Both of these are pretty self-explanatory.)
1968: Humphrey (If you watch CBS's Election Night 1968 coverage on YouTube, you can hear cheers in the background when they called New York for Humphrey.)
1972: McGovern (An overwhelming majority of journalists voted for him over Nixon.)
1976: Carter
1980: Carter
1984: Mondale
1988: Dukakis
1992: Clinton
1996: Clinton
2000: Gore
2004: Kerry
2008: Obama
2012: Obama (Obviously for both 2008 and 2012.)
I don't get this question. It seems pretty clear to me that it's been all Democrats since at least 1960.