There are some numbers occupied by multiple franchise greats, numbers that call to mind vastly different eras of successful Falcons football and icons both past and present.
Inarguably the best player ever to wear #4 in Atlanta was Brett Favre, but his ignoble run with the Falcons makes him a non-starter for this list. This is a man who attempted four passes in a Falcons jersey, throwing two picks, so you can't consider him eligible unless you're some sort of loathsome half-Packers, half-Falcons fan.
If you move past Favre, you're left with either Jay Feely or Dan Styzinski, a kicker and punter. Styzinski spent six solid if unremarkable seasons in Atlanta as their full-time punter, while Feely spent four seasons as the Falcons' kicker and put up pretty unremarkable numbers there, as well. I'd consider a kicker more impactful than a punter, if only by a little bit, and so #4 belongs to Jay Feely. A man with a 76.5% field goal percentage.
Let us never speak of this number again.