I think I've made my case for Cowher on at least four occasions;  signing him immediately restores a level of respect to the franchise.  Bringing him on board immediately makes him the face of the team; something it has lacked all season.  He commands respect from every single player, young and old, due to his previous success.  Very little flight risk, possible he would remain with the team for a decade.  Hard to argue against a Hall of Famer.

Singletary would be an interesting hire, and he definetly has credibility due to his stellar career on the field.  However, at this time I think it would be prudent to look for someone with previous experience (sucess) as a head coach in the NFL.  I wouldn't be upset if the team were to go with Singletary, but he is more of an unknown than Cowher.

McDaniels is a hot name because his team is on its way to an undefeated season, and they're lighting up the scoreboard.  They have wayyyyyyyyyy more talent at the qb/wr positions than the falcons (and most other nfl teams) have ever seen, ever, in their entire history.  I would be a bit wary of giving McDaniels the job because he would have to be mentally deficient to really mess up an offense that features Brady and the Moss-kateers.  He does have some things that work in his favor; he would be a splashy hire, he comes from the Belichick coaching tree, and he knows how to work with veterans with sizeable egos, all good things.

Whatever the Falcons do, I sincerely hope they stay away from Mike Martz as a head coaching option.