Depends on where in the draft you are picking, but most would tell you to stock up on RBs early and often. I think this year's a little different with all the rbbc's, Definitely look for workhorse RBs, but you should be able to get good RB value in the early-mid rounds. (Pierre, Lynch, Wells, Moreno, Ward, Bush, etc should go around rounds 3-5. There's a shortage on good WRs so if you can get a Moss, AJ, Fitz late in the 1st or early in the 2nd, do that instead of a Barber/Portis second tier RB. Definitely wait on kicker and defense until the last few rounds of the draft. You have to let the QBs come to you. dont try to predict it. if a good value QB is dropping in the draft take him. Just dont reach for them too early. The later you take a QB, then the earlier you should take a backup QB. Also dont forget to snag your top RB's backup later in the draft. but not before most or all the starting RBs are gone.
just my 2 cents. has worked well for me so far. I liek to have a copy of average draft positions handy, that way you are drafting good value instead of just filling out positions. I wouldnt plan on going 3 RB/3WR in 6 rounds, but just see how the draft goes. You might get a top TE or Top QB dropping to you and you have to be able to recognize it if it happens.