I always draft whoever is a better value, regardless of need. My opinion is that, if I really think this RB3 is going to be better than this WR2 this year, then I draft the RB3 and after a couple of weeks I trade him for that WR2 plus a little extra. It helps that all of my leagues are long-running affairs, so I've established a reputation as a fair and willing trader and have developed strong trading relationships with at least 2-3 people in each of them. In a no-trade league (either a league with rules against trading, or a league where no one trades), it's important to address your starters before acquiring too much quality depth. Of course, I usually consider my RB3 to be the equivalent of a starter, because how often do two RBs make it through an entire season without getting injured? So once again, it's a question of best player available.