Also, see the Sound page for information on APM interactions with the sound system. The Debian kernels do not include APM support. While you're at it, recompile the pcmcia package as well. The kernel will attempt to reduce power consumption while idle, and it also supports turning off the system completely upon a system halt. Pressing a key will wake the system up immediately.
Standby leaves the system lights normally lit.
Suspend causes the system to slowly flash an amber light under the computer icon. Note that suspend DOES use battery power and that if the battery runs out, the system will halt entirely. If the system is turned back on within 10 minutes, the contents of RAM are unchanged and the system can be used immediately. After 10 minutes, or if the battery has been changed, the contents of RAM are restored from disk, an operation that takes about 20 seconds. When it is hibernating, there will be no lights on, except maybe the battery light if the system is plugged in.