Based on this season's track record, I won't be surprised if the Friday lineups of ABC, NBC and Fox were free of scripted shows next season.
ABC: In 2008-9 ABC had all unscripted Fridays, this season they tried Ugly Betty at 9pm, and it averaged a 1.2 rating. I'd look for them to go back to (or keep, depending on your perspective) their line up of Supernanny, Wife Swap and 20/20 or something close to it, next season.
Fox: Had an all unscripted Fall line up on Friday in 2008-9, then did worse in the ratings with scripted shows in the Fall on Fridays in 2009-10. Kevin Reilly made a lot of noise about wanting to reintroduce scripted shows to Fridays before the 2009-10 season started. I'd expect that noise to disappear and Fox to be back to all unscripted on Friday's again, although I think there is a small chance that Lie to Me and/or Fringe gets sent to Fridays in a last chance exile (ala Terminator last spring, and Ugly Betty and Law & Order this season).
NBC: Gun shy with its affiliates (at least until the Comcast deal closes) over The Jay Leno Show, I'd expect NBC to have scripted shows on Monday-Thursday at 10pm next season, but I don't expect them to go scripted show crazy overall. Instead, look for Dateline NBC and a couple other unscripted shows on Fridays where they should be relatively free from affiliate whining.
CBS: The only network to schedule all scripted shows on Fridays in the last several years, I don't expect them to change that, but Friday's are dragging down their overall numbers a lot more this season.
This season CBS Friday dramas are averaging 55%(Numb3rs), 60% (Medium) and 66% (Ghost Whisperer) of CBS's overall adults 18-49 ratings average. Last season they averaged 66% (both Ex-List & Flashpoint), 73% (Numb3rs), and 83% (Ghost Whisperer). So Friday's are just as expensive, and not nearly as successful for them as they were in the recent past. I don't expect Fox, NBC or ABC are looking at CBS's results and thinking "Let's get us some of that!".
CW: With the CW only programming 10 hours (only 9 original hours) a week, I'd expect them to continue a scripted show at 8pm and a repeat at 9pm on Fridays.