Snarfer: Easy to use RSS reader for Windows
You can easily arrange items by subject, date, or source. Clicking on the date tab gives you a Google Reader-like "river of news" where you see each item in chronological order, rather than by source. Unfortunately there doesn't seem to be a way to save this view, so you'll have to click "date" each time you select a folder you prefer a river-style view.
The program does a great job of importing feeds from OPML files. We were able to import over 400 subscriptions in a matter of seconds, and it only took a few minutes for Snarfer to grab updates from each feed.