Since you specifically mention airports and hotels, note that many of these wifi services, even though they show a strong signal on your nook color, won't connect until you accept their terms of service. To rule this out, with wifi on and a strong signal strength seen, open your browser and see if there's a "I accept the wifi site's terms of service" button that needs to be clicked.
This may not be your issue given the rest of what you mention, but I've found it to be a problem for me, especially when trying to use email or Pandora or other internet-req'd service that doesn't open a browser to see the button that needs to be clicked. It'll be a quick test showing you one way or another if this is the source of the problem.
At least you've got the CM7 option to connect. For what it's worth, I can connect with B&N1.3 and CM7 to all wifi sources I've tried, both open and those secured with WPA2 so it's not a general 1.3 issues but appears to be something fairly unique to your situation.
It may be worth a look into having your nc's 1.3 "forget" wifi sources that won't connect for you, then reconnect with them. I believe I had one instance where I couldn't connect to my home router--a forget and reconnect got me going again.
If none of this works, there are a lot more knowledgeable folks here that should be able to offer some help.
Just one request--since wifi connection issues do crop up on these forums now and then, please report back with your final status--and if successful as we all hope, describe what your solution was. Good luck.