Radio station program directors assemble playlists from all the music available to them -- and they rotate their playlists as time marches on. I've decided to do the same thing with my Twitter and FriendFeed subscriptions.
From now on I'll subscribe to 50 Twitter feeds and 50 FriendFeed feeds. That's it. Over time I'll go back and add in folks I used to subscribe to, and add some new ones, too. Just like those program directors, I'll rotate out a commensurate number of choices, and the process will repeat every couple of months.
It got to the point where I didn't even know who I was subscribing to. I never noticed when someone went silent. Speaking only for myself, I prefer voices who post occasionally -- not too frequently and not too seldom. I also am trying to monitor voices from many segments of the tech industry -- media, PR, investors and so on.