If 2006 was the year Thursday night became a battleground for programmers—stacking ABC’s “Grey’s Anatomy,” CBS’s “CSI,” Fox’s “The O.C.” and, at one point, NBC’s “Studio 60” against each other in the same 9 p.m. slot—then 2007 could be called The Year Wednesday Became Important.

Long a night for big-tent reality franchises (“American Idol,” “Dancing With the Stars”) to trample over their scripted counterparts, Wednesday is now the new fall destination where the networks are placing some of their biggest bets on original programming. ABC has two of its most anticipated dramas slated for 8 p.m. and 9 p.m. in “Pushing Daisies” and “Grey’s” spinoff “Private Practice”; CBS is pairing controversial reality show “Kid Nation” with established hit “Criminal Minds”; Fox has the Kelsey Grammer-Patricia Heaton sitcom “Back to You” coupled with Brad Garrett’s “’Til Death” preceding “Bones”; and NBC is looking to blow its biggest hole yet in the night with “Deal or No Deal” and its “Bionic Woman” update.

Even The CW hopes to snare a good portion of the 18-to-34 demographic away from “Private Practice” with “Gossip Girl,” the new teen soap from “O.C.” creator Josh Schwartz. Based on pilots and early clips alone, The CW drama is an early fave of buyers both from a brand standpoint (T-Mobile’s Sidekick has a starring role in the show’s pilot) and in scheduling.

“It could be their new ‘Dawson’s Creek’ or the new ‘Felicity,’” said Laura Carracioli-Davis, exec VP and director of entertainment for Starcom, pointing out that the year-old network’s distribution limits it from doing any Big Four-level numbers. Still, most of the agencies who submitted their predictions to Advertising Age think “Gossip” will grab around a 4 share and say the show could eventually build upon its “Top Model” lead-in.

After a cutthroat first two hours, the 10 p.m. Wednesday time period has also become more crowded, with ABC’s “Dirty Sexy Money” and NBC’s “Life” looking to take a chunk out of the commanding lead held by “CSI: New York.”

Shari-Anne Brill, Carat’s VP of programming, said “Dirty Sexy Money,” with its steamy premise and stars such as Peter Krause and Donald Sutherland, could also retain the majority of the females from its “Private Practice” lead-in.

Although Wednesday is regarded as the night likely to garner the largest increase in total viewers, the pick for fall’s most-watched show is less unanimous. “CSI,” the top-rated show of the past several years, took a sizeable hit going up against “Grey’s” this season, and participating agencies predict the two shows will split the top-share honors with a 17 share. Only one other fall show is seen as likely to put up similar numbers: ABC’s “Dancing With the Stars,” which the agencies predicted will take an 18 share.

Fox drama “House” could become the new season’s surprise ratings champ based on its strong midseason performance this year—retaining and even building upon its “American Idol” lead-in. Buyers believe it could get a 14 share in the fall.

“That show just keeps on getting better and better,” Ms. Brill said. “It doesn’t have ‘Idol’ to worry about anymore. To think, that show did almost nothing until it aired behind ‘Idol.’ … It has so many additional opportunities now. Plenty of shows have had ‘Idol’ as a lead-in and didn’t even go anywhere.”