I would like to join in here. I have a Thinkpad T20 I just put 2.6.0-test11 on and APM will only suspend properly if the power plug is pulled out of the back (thanks for that tip, btw). With power connected, it plays a high-low beep and turns off screen and HD without suspending properly (and if left too long, may not come back to life).
I believe I read somewhere there is some kind of settings to override power features when AC power is connected. Perhaps this problem is related to that. I tried running "apm -i" and "apm -n" but it wouldn't recognize the commands as set out in the man page.
If I stop apmd AND rmmod apm then I can suspend by closing the lid (hardware suspend I guess) but then I have no battery monitor capability.
I tried ACPI but it would not work without =force as a kernel parameter and when used, did not cleanly come back from a suspend.
APM worked perfectly in 2.4.20 which is what I used up to today. Are the APM/ACPI people out there?
an interesting email on "suspend rejects" caused by kernel drivers from a year ago or more:
http://open.nit.ca/lists/archives/apmd-list/msg00006.html