While I was trying to hunt a bug, I found a very strange behavior when I open the laptop lid, caused by gnome-settings-daemon:
1) the first bulk of key-presses lag some seconds (no matter when I hit the
keys, it can also be 1 minute after I opened the lid) then the keyboard goes
back to normal work
2) some panel icons (apparently all applets) suddenly disappear and reappear
(like a flash). This does not always happen

I've opened a bug here https://bugs.launchpad.net/bugs/524830

I'm wondering if you also suffer from this problem. I have 2 laptops (HP and DELL) and both have it.