The Niners just barely made it past the Falcons in the playoffs last year to win the conference championship and a trip to the Super Bowl. Since then, the Falcons have done nothing but improve.
To improve their running game, they picked up three-time pro bowler Steven Jackson from the Rams. To improve their defense, they picked up DE Osi Umenyiora, CBs Desmond Trufant and Robert Alford and several other rookie prospects.
One interesting fact, though its meaning is uncertain until we get closer to the game, is that the Falcons' bye week is 10 weeks before their meeting with the 49ers, and last season the Falcons were tied for having the oldest team in the league. Take that as you will.
A statistical note: While the Falcons defense certainly didn't perform at NFL-topping standards last year in terms of yardage allowed per game (ninth-worst), they managed to keep those yards from converting into points. Last season the Falcons actually allowed the fifth-fewest points per game.
Passing allowed: 242.4 yds/game, 7 yds/att
Rushing allowed: 123.2 yds/game, 4.8 yds/att
Points allowed: 18.7