Fall 2006 was when year the Thursday landscape completely changed thanks to ABC bringing Sunday hit Grey's Anatomy over to the night.
ABC: Grey's Anatomy came to the slot in fall '06 and dominated staple CSI in the demo, but its declines the past couple years have been hefty. Still it's the favorite to win the hour because CSI has done more than its fair share of declining as well. It posted a 5.7 original average in '08-'09.
CBS: The eye has long offered the father of its crime drama family CSI in this timeslot and will continue to do so for '09-'10 but big hit The Mentalist moved to the 10:00 hour and may have its eye on the slot in the near future. CSI averaged a 4.8 demo in originals last season but that doesn't tell the whole story as it got spikes for cast upheaval moments and was a substantially stronger show in the fall than in the spring, when it dipped all the way to a 3.4 for its season finale. The return of Jorja Fox and some tweaking of the Laurence Fishburne character could bode well for '09-'10 though.
FOX: ABC and CBS have offered staples in this timeslot, but Fox has certainly not. The O.C. had its disastrous final run here in fall '06 and winter '07. While 5th Grader helped the 8:00 hour in the spring, Fox had nothing to offer at 9 and went with repeats of Family Guy and a repeat/original mix of Trading Spouses. Don't Forget the Lyrics! debuted in summer '07 and nailed down the timeslot safely for all of '07-'08 but it and 5th Grader were moved to Fridays in fall '08 and Fox went with another run of Kitchen Nightmares which did much worse than its fall '07 sleeper success on Wednesday. For winter and spring of '09 the net went with Hell's Kitchen which was a marked improvement on Nightmares. This year, it's a big risk with sci-fi drama Fringe joining the hour.
NBC: The peacock opened up '06-'07 with Deal or No Deal in the slot but soon abandoned it in favor of a second hour of what they called "Comedy Night Done Right." The only time NBC has shrunk this block since then in the regular season was for the writer's strike run of The Celebrity Apprentice in early 2008. The block was initially top-heavy with the 8:00 hour doing pretty well and the 9:00 combo of Scrubs and 30 Rock really struggling, so NBC got a little bolder in fall '07 by moving The Office to the second hour. Scrubs was the post-Office occupant at 9:30 but was switched with 30 Rock which has seen growth in each of its three seasons (thanks last year to Tina Fey's impression of Sarah Palin) and will occupy 9:30 in '09-'10 starting in October, after the slot briefly goes to newbie Community for some post-Office sampling. The Office averaged a 4.3 in Thursday originals and while it showed signs of decline toward the end of the season, it did beat CSI in the demo for the first time ever. 30 Rock averaged a 3.3 in originals.
CW: The CW has aired Supernatural here since its inception and will continue to do so in '09-'10. The only exception was a brief tryout for Reaper during the writer's strike in spring 2008, but it did worse than Supernatural usually does and plans to bring Reaper back on Thursday in season 2 fell through when the net decided to return it to Tuesday to go up against Idol.