The longtime home of NBC's Law & Order, a growing CSI:NY caused NBC to move the tentpole out of the slot in fall of '06, and since then CBS has been stable while the other two nets have had a lot of upheaval.
ABC: For the '06-'07 season ABC cancelled Invasion and The Evidence, the season's previous Lost lead-outs, and tried another newbie in The Nine. It failed pretty badly and was replaced first by Primetime: Live and eventually by Lost, which the net decided was incapable of leading into anything. For the next two falls the timeslot housed Dirty Sexy Money, but the seasons were cut off first by the strike and then by cancellation. In early '08 the replacements included drama failures Cashmere Mafia and Men in Trees, then a post-strike run for Boston Legal. In early '09 Lost made its return to Wednesdays at 9 and it had a couple lead-outs, first '70s cop show Life on Mars and then cop dramedy The Unusuals. Neither of them lasted either so it's yet another newbie for ABC in remake Eastwick, which will lead out of two hours of new comedy.
CBS: The eye debuted CSI: New York in this timeslot in fall of 2004 and has not aired anything else here since. It was a stable player on a year-to-year basis in '08-'09 averaging a 3.4 demo and returns there for fall '09.
NBC: If one event can signal the beginning of NBC's problems on Wednesday night, it was probably newbie Kidnapped showing up completely DOA in the fall of 2006. Rather than bring back longtime tentpole L&O, they briefly aired Dateline in the slot and had a midseason run for Medium ready to go by November. For fall '07 they had cop drama Life in the timeslot which started in medicore fashion but held up well enough during Bionic Woman's complete meltdown that it got another season but saw its first one cut off by the writer's strike. In winter '08 the net returned Law & Order to its longtime home. For fall '08 it was failed sophomore drama Lipstick Jungle, but it was quickly shifted to Friday and Law & Order was back in the saddle by November. Don't count on L&O to the rescue this year as the net should stick with The Jay Leno Show here and in all weeknight 10:00 slots for all of '09-'10.
Cable Notables: FX offering Nip/Tuck always drums up some demo interest, as will Comedy Central's animated veteran South Park and newbie leadout Secret Girlfriend.