The Texans moved to the top on Tuesday following their 13-6 win over the Chicago Bears, while the Falcons dropped to second after their first loss of the season, 31-27 to the New Orleans Saints.
Houston (8-1) was a unanimous choice, receiving all 12 first-place votes and 384 points from The Associated Press' panel of media members who regularly cover the league.
Atlanta, the NFL's other one-loss team, received 362 points, while the Bears remained third with 341 points. San Francisco was fourth with 339 points, and Denver moved up three places to fifth with 334 points.
"Tough victory at Soldier Field earns Texans the No. 1 spot," said Sporting News' Clifton Brown.
Newsday's Bob Glauber singled out the Texans' defense, which forced four turnovers and sent Bears quarterback Jay Cutler to the sideline with a concussion.
"Some well-earned fist pumping from Texans defensive coordinator Wade Phillips, whose unit one-upped the host team's D," Glauber said.
Houston was first in the power rankings for three weeks earlier in the season, but relinquished the spot to Atlanta after losing to Green Bay on Oct. 14.
Atlanta's loss drew a variety of comments.
"Trust me, that loss will be good for these guys," CBSSports.com's Clark Judge said. "Now, the pressure they feel is not from trying to keep an undefeated season intact; it's trying to win a playoff game."
Then again, some voters saw a loss coming.
"The season-long problems rushing the football and stopping the run came back to bite the Falcons in their first loss against New Orleans," said Foxsports.com's Alex Marvez.
Despite the loss, the Bears held third as they prepare for Monday night's showdown against the 49ers, whose quarterback Alex Smith left Sunday's game with a concussion.
Peyton Manning and the Broncos are on the rise after their fourth straight win.
"Peyton + defense + special teams (equals) quite a combination," said ESPN's Chris Berman.
The New York Giants, meanwhile, fell four places to No. 10 after losing to Cincinnati, which improved five spots to No. 17.
"Another year, another second-half swoon for the Giants," noted Newsday's Glauber. "This time, Eli Manning's the biggest issue; no TD passes in his last three games. That hasn't happened since his rookie season."
The New York Jets are sliding, too, down to 26th after their third straight loss.
"This team is a mess, no matter what Rex Ryan or anyone says," said Sporting News' Brown.
Philadelphia is trending downward, as well, falling four places to No. 24 after its fifth straight loss. Eagles coach Andy Reid is under fire, quarterback Michael Vick has a concussion, and rookie Nick Foles might wind up starting in Sunday's game against Washington.
"In two months, there won't be enough brooms for this housecleaning," said the Tampa Tribune's Ira Kaufman.
Indianapolis remained 12th after its win over Jacksonville. The Colts are at the Patriots this weekend.
"Andrew Luck takes the baton from Peyton Manning in the Colts-Patriots rivalry," Glauber said. "Win or lose, Colts very much in the playoff hunt."
Don't count out New Orleans, either. The Saints jumped four places into a 13th-place tie with Tampa Bay.
"Right now they probably deserve to be higher ... but they have early failures that can't go away just yet," said SiriusXM NFL Radio/CBSSports.com's Pat Kirwan. "New Orleans is running the ball, Brees is unstoppable, and the defense is getting more pressure on opposing quarterbacks."
Jacksonville is No. 32 and last.
"Mike Mularkey has taken to throwing things. And some think his throws have been more impressive than Blaine Gabbert's," the Chicago Tribune's Dan Pompei said.
Comments on the Houston Texans by the AP Pro32 panel (ranking in parentheses):
HOUSTON TEXANS (1)
Chris Berman (ESPN, 1) -- Forceful on both sides of football.
Clifton Brown (Sporting News, 1) -- Tough victory at Soldier Field earns Texans the No. 1 spot.
Cris Collinsworth (NBC Sports, 1) -- (not yet posted)
Rich Gannon (CBS Sports/SiriusXM NFL Radio, 1) -- Impressive road win shows that they can bang with anyone, anywhere, anytime!
Bob Glauber (Newsday, 1) -- A statement game for the Texans, who slogged through the rain and muck at Soldier Field to outlast the Bears. Some well-earned fist pumping from Texans defensive coordinator Wade Phillips, whose unit one-upped the host team's D.
Rick Gosselin (Dallas Morning News, 1) -- Arian Foster has scored a touchdown in all nine of the Texans' games and is their MVP candidate in an 8-1 season. He has 12 touchdowns in all, 10 rushing and two receiving.
Clark Judge (CBSSports.com, 1) -- The Texans' defense is good enough to get them to the Super Bowl. My question: Is Matt Schaub?
Ira Kaufman (Tampa Tribune, 1) -- They can beat you in a Texas shootout or a muddy defensive struggle. Choose your weapons.
Pat Kirwan (SiriusXM NFL Radio/CBSSports.com, 1) -- The Texans deserve the top spot. They went on the road to Chicago this past week and won in very tough weather conditions. Their defense overshadowed the Bear defense.
John Lynch (Fox Sports, 1) -- Impressive win for the Texans in an old school, bad weather, tough, brawl vs. the Bears in Chicago. They have earned and belong in the top spot.
Alex Marvez (Foxsports.com, 1) -- I perceived Chicago as the more physical team entering last Sunday night's game. Houston's 13-6 road victory proved me wrong.
Dan Pompei (Chicago Tribune, 1) -- They proved they are no fluke by winning against a tough Bears team in bad conditions Sunday.