Reality shows are tweaking old formulas

"The Bachelor 8"
Before it had "Dancing with the Stars," "Lost" and "Desperate Housewives," ABC had one show to cling to: "The Bachelor." Thus, with other hits on its hands, it's just a little surprising that the network is bringing back its withered dating series for yet another run. The show heads to Paris to see if the City of Light can help to spawn a successful relationship. (Because that worked so well for "Joe Millionaire 2.") Chris Harrison returns to host, and to relentlessly tease undramatic moments with hyperbolic statements ("Coming up: The most amazing bachelorette sneeze ever").

Premieres in January, after football; airs Mondays at 8 p.m., ABC

"The Biggest Loser 2"
Last season's surprise hit managed to tackle a significant subject, obesity, without always playing to the lowest common denominator. It was so successful that NBC pushed back its premiere from summer to fall, showing that the network believes in its strength. Like syndicated "Starting Over," "The Biggest Loser" was heavy on motivation and relatively low on cheap tricks, such as tempting the competitors with junk food. For season two, trainers Bob and Jillian will return, as will host Caroline Rhea. But the old house is history, so the new cast will have a new gym and living quarters as they fight to lose weight and win the game.

"The Biggest Loser" is also spinning off a version of single-episode weight-loss competitions between groups of people. NBC says these episodes will be "themed" and could end up "pitting town vs. town, family vs. family, bride vs. bride, co-workers vs. co-workers and more." This new show will have a different host and new trainers, and a premiere date has not yet been announced.

Premieres Sept. 13; airs Tuesdays at 8 p.m. ET, NBC

"Extreme Makeover: Home Edition"
How will Ty make us cry? That's the big question as "Extreme Makeover: Home Edition" enters its third season. The series makes "Trading Spaces"' renovations look like kids cutting up paper, as Ty and his team of designers bulldoze or gut the houses of deserving families. The series is nearly single-handedly responsible for causing a swing in reality TV shows from cruel, hoax formats to feel-good, uplifting shows. But with an ever-increasing amount of emotional intensity, can the show continue to top itself, or will we merely choke up — rather than bawl uncontrollably — when a family sees its new house and their 48 new plasma TVs for the first time?

Premieres Sept. 25; airs Sundays at 8 p.m. ET ABC