Canon 5D mk II vs 50D at 1600 ISO

[gmorstad]

I am trying to decide if I'm going to buy the 5D mk II or the 50D.  I should say I already have the 30D but that's not a big factor.  The big question I have is this.  Is there a noticeable difference between them at 1600 ISO printed to 16x20?  I am going to shoot weddings and portraits.  I have the 17-40L along with plenty others, so lenses are not an issue.  Final print quality is the only issue. 

Thank you