So, full disclosure, I have a head-over-heels e-crush on Matthew Berry. (Don’t worry, Current Mrs. Roto, it’s purely digital–I am happily married with 2 kids.) I just really enjoy his writing, and I think he gives very sound advice. But he is human and can’t predict the future, so I don’t take his word as law (and neither should you.)
On the other hand, many of the gurus out there have opposing views on certain players and teams, and you can drive yourself crazy when it comes to sit/start decisions if you read too many opinions. So my advice is to pick the guy(s) (or girl) you like best and have had most success with and use them as your primary source.
My two favorite sources for information are ESPN Insiders and Rotoworld (both are paid subscriptions.) You can get general info from espn.com, but paying for the Insider subscription gets you more in-depth analysis and Matthew Berry (swoon….) Again, I will reiterate some of that information here, but if you want the first hand “expert” commentary and more up-to-the-minute information, you should pay for those sites.
Other sources I like are TheHuddle.com and FootballGuys.com. Finally, most of the fantasy leagues I have played in have been Yahoo! Premium leagues, which also gives you helpful weekly posts from several fantasy gurus (though your competitors in the league will have all that same information as you).