I know the (D) label has been increasingly ommited for Demcoratic politicans.  I read a recent post her eon NB that discusses this so I put together this report called "THE CNN REPORT" which basically analyzes over 100 articles dealing with 10 politicians (Republicans and Democrats).  I got the  idea back when I was reading the breaking news about Blago on CNN late last year and had to google his name just to find out what party he belonged to.  

 Access it here:
http://www.firesusan.com/THE_CNN_REPORT.pdf

(I don't have hosting so a friend is hosting it) 

The CNN REPORT looks at 10 politicians: 5 republicans and 5 democrats.  Then it takes a loot at their articles on CNN.COM and finds out where and when CNN published their party affiliation.  You will be pretty surprised (actually, its expected, so you really won't) at the results.  It's pretty much in line from what you report here about news agencies including the (R) but omitting the (D).

Let me know what you think.