Not the OP, but for instance:
Peter Nickeas at the Trib does real-time crime reporting from the South Side of Chicago; @peternickeas
I get a pretty constant feed of Middle East stuff that I don't see elsewhere from Laura Rozen (though I'm uncertain of her ideological tilt, she pulls in lots of random other sources); @lrozen
There are a couple court reporters in Chicago that I've picked up.
Saved You A Click does a pretty good job of condensing most of modern journalism into a short Twitter feed; @SavedYouAClick
M&A/corpdev comings and goings in the Valley, startupland's "Weddings Section", that's @pinboard.
Of course, there's @scotusblog.
There are lots of kinds of news that Twitter is just a lot better at delivering than websites or (gag) RSS. Since it's so easy to compose twerps, especially once you get the hang of it, it seems like it draws a lot of reporters in who would not do real-time reporting so aggressively in a different medium, but will do it so long as the expectation is set that they only have to tap out 140 characters an hour.
This is also an advantage Twitter has over Facebook.