I recommend that under the Power Management control panel you turn off Processor Cycling and set the CPU to run at its fastest. Then close the lid. This gives the most predictable behavior. Closing the lid has different functions under Linux depending on the status of AC power - it simply turns off the LCD when AC is plugged in, but it puts the system into suspend mode if AC is unplugged. Note that this is NOT how it works under Windows.
Sleep mode seems to do nothing other than turn off the monitor.
Sound Sound under Linux works very well. Getting it running is a little tricky, but once you get it going it works very well. So, here's some info to help get sound going. The APMd package for download above includes all of the files I'll be mentioning here. First, you want to set up your BIOS to deal with Linux and the sound card as the script is expecting it.