How to find out why it takes so long for the sign in form to appear after opening the lid on my Macbook Air Whenever I open the lid on my Macbook Air running Lion and and try to sign in, it takes a really long time for the sign in form to appear. (This is the sign in form you see when the Mac is on but the lid is closed, not the one you see after turning it on after being powered off.)

I see a black screen with the normal arrow cursor for nearly a minute. Sometimes the form shows up, and sometimes the screen just goes black, at which point I have to close and reopen the lid for the sign in form to show up.

This is a corporate machine, and a coworker thought it was waiting for Wi-Fi to reconnect, but the problem still exists when I turn Wi-Fi off. What's really going on? I would imagine that not all Macs have this problem. How can I figure out why this is happening? Could installed software be preventing the computer from waking quickly? If so, is there a way to track down the culprit?
The MBA goes into hibernate mode after several hours of being asleep. Also, if you close it and then open it again rapid the computer will be mid-cycle in going to sleep and will want to finished that before attempting to wake up (which can take some time also). In general Macs today take longer to boot up than they did, but they sip much less power when not being used. 

A similar post is here:

MacBook Air takes an eternity to come out of sleep

And some solutions are posted