I'm on a Lenovo T400 laptop.
In the past I had suspend problems on every second version of Ubuntu (at least it feels like it), but in 11.04 it was working perfectly. Now, after the upgrade to 11.10 closing the laptop lid does no longer initialize suspension.
When I choose 'Suspend' from the shutdown menu it works perfectly, so this does not seem to be an issue with suspend itself.
The options in
System Settings>Power are of course set to suspend in case of closing the lid (both for battery and AC poer).
Note: I have no idea if this is of any importance, but I'm running the gnome-session-fallback stuff, as I just hate the Unity desgin.