Before the NFL Combine some draft gurus propsed that WR Jeremy Maclin was the best WR in the draft. Better than Michael Crabtree and certainly better than Darrius Heyward-Bey. While he ended up being the third WR drafted, he landed in easily the best fantasy spot of any of those three guys. If Dick Cheney had you strapped to a waterboard during your fantasy draft -- just one reason of many you don't want to invite Cheney to your draft -- and forced you to draft a rookie WR, then Maclin is the guy you want to take.
Maclin steps into what might be the most well-rounded offense in the NFC. QB Donovan McNabb is a star. Running back Brian Westbrook is an all-around weapon and this season he has LeSean McCoy to help out. (The Eagles' roster now includes a Sean, a DeSean and a LeSean. What's up with that?)
WR DeSean Jackson had a fantastic rookie season last year, leading the Eagles with 912 receiving yards and adding two receiving TDs. He returns as the Eagles' WR1 and Maclin is now the WR2. With Jackson and Westbrook around to keep the opposing defenses honest, Maclin should have a very good rookie year. Maybe not as good as Jackson's stats from last year, but close. Maclin will also serve as a return man occasionally, so if your league scores for that keep that in mind.
The addition of Maclin also improves the fantasy value of McNabb and (especially) DeSean Jackson. I think Jackson is all but a lock for 1000 receiving yards this year, and I wouldn't be surprised if he exceeded 1200 yards.