I finally got sleep to work on OSX 10.6.2 on my Dell Inspiron 1520.
So happy, now my productivity is that much better. Don’t have to close all my applications and shutdown the computer.
Can just pause in middle of working on something and pick up where I left off.
The problem was all due to hardware on the USB ports that kept waking the laptop from sleep. The USB UHCI/EHCI drivers were probably connected to USB BlueTooth or USB camera.
Follow the instructions here to fix USB UHCI/EHCI controller settings. This requires you to set/modify your DSDT.AML file properly.
Quartz/CI is working using NVResman & NVInject64.Quartz/CI is needed to make sure DVD Player and/or VLC will play video properly.