I'm a firm believer that wide receivers are almost always your best keeper or dynasty league options these days to target early. For starters, they are good for a sustained period of time, and the elite ones tend to stay on top year over year. That's reflected in a study we've done on bust rates.
Additionally, wide receivers don't seem to age or lose tread on their tires quite like running backs do. Someone like Andre Johnson still warrants keeper consideration and is considered a top 12 option to many despite being over 30 years old and not having a good quarterback throwing him the rock. On the flip side, a running back counterpart over 30, like Steven Jackson, doesn't provide as much upside.