With the way fantasy football is changing, as well as the actual game itself, it's making more emphasis on quality WR's and a very good QB. The general consensus used to be to draft two rb's in the first 2 or 3 rounds, but with so many backs now sharing carries with others, it's making the running back position way less valuable.
And especially this year, the RB class is very top heavy with guys like CJ, AD, and MJD, but then the rest are most likely splitting carries in a running back by committee. I did a very early draft in a random public league i had joined on Yahoo! today, and i only drafted one running back in the first 4 rounds, and that was just because i was shocked he had fallen down to me. My 2nd round pick was Peyton Manning, just because of the value(i still hate myself for doing it), and my 3rd and 4th picks were both WRs(Boldin and Ocho Cinco). It was especially critical in this league because alot of leagues are starting to lean towards a PPR format, and a guy like Andre Johnson gets put over most players(he went 4th overall in this league). And solid receivers are much harder to come by in the FA pool during the season than a running back is.
But reiterating what the guy above me said, it's all about how the rest of your league picks, and however they strategize you should counter it and beat them. CJ is probably the safest pick in the draft this year.