I think I would go with
1. AJ
2. Fitz
3. Smith
4. Boldin
5. Marshall
#5 was a toss up between Marshall and Calvin Johnson, but I gave the nod to Marshall because right now he's in a system that better showcases his talent. I picked AJ for #1 instead of Fitz because AJ led the league in receptions and yardage this season and appears to only be getting better as time goes on. Also, Fitz has Boldin to rely on across the field. AJ has Kevin Walter (a good player but a journeyman receiver) across the field, and Walter finished the season with 900 yards and 8 TDs. To me, that speaks volumes about AJ. As for Smith, he might be on the decline a little, but his 18.2 YPC is just ridiculous and he does it with that turd Delhomme tossing the ball.