I've been using Facebook's Twitter Application so that my "tweets" (hate that word, not that "blog" is a fave either) go to Facebook. That's handy since there are lots of convenient apps on various platform for creating twitter updates -- and it lets me simultaneously communicate with my very few friends who are Twitter-centric.
I don't want to have monitor Twitter and Facebook for updates however. So I've turned off all the FB email notices and I've added the wall and notification Facebook feeds to Google Reader.
That does a great job for FB -- better than the native app really. Unfortunately Twitter uses authentication rather than unique URLs, and Google Reader doesn't support authentication.
Which is where FreeMyFeed (Free Your Feed From Authentication) comes in. You provide the service with your Twitter credentials, then it encrypts them into a Feed URL that you keep. When requested FreeMyFeed decrypts the URL and logs in. Yes, there are obvious trust issues here.
FreeMyFeed claims they don't store the Twitter credentials, but of course they could cheat. So if you go down this route use a unique pw with Twitter that's not tied to anything important -- that way only your Twitter account is at risk. With this method I can monitor both Twitter and FB from Google Reader.
Oh, and Twitter needs to adopt the same "secret URL" approach everyone else uses. The authentication requirement for Twitter feeds is extremely annoying.
Update: You can also use Yahoo Pipes to make an authenticated feed accessible to Google Reader and FeedBurner. I might try the latter.
Update 2: I switched to the FeedBurner technique because it turns out (who knew) my Gmail authentication also gives me FeedBurner authentication (feedburner.google.com). The way you encode the authentication credentials is a bit gross (see the link) but it works quite well: "you now need to add your twitter username and password into the link as follows http://username:firstname.lastname@example.org/statuses/friends_timeline/nnnnnnn.rss"