Ubuntu :: Auto Suspend After Certain Amount Of Time?

Most nights I fall asleep watching tv or movies. I want the computer to go to sleep after I do. Under Power Management Properties I have "put computer to sleep when inactive for 1:00" yes - to " spin down hard disks" and "put display to sleep when inactive for 1:00"

I'd say 65% of the time I wake up and the computer is running, not suspended, and 45% of the time the monitor is still on. Over the past 8 months or so I have been trying different media players. I tend to have the same problem of the computer not sleeping with all of them. (Banshee, Miro, xbmc, boxee, vlc, totem, )

1. Is there a process I can look for that may be running some of the time that would hinder the suspend function?

2. Is there a simple script I can write for "suspend in 90 minutes"

3. I think I remember seeing way to do this from the CLI with pm-suspend, yeah?

Edit- I found this http://bit.ly/hpThVM
Things I tested that didn't work
~$ sudo echo pm-suspend | at 12:27
~$ sudo sleep 30s