Just thought I'd let you know what I worked out with the same problem you are experiencing. The problem must be dinfintely be with the 4965AGN Wireless NIC driver manufactured by Intel and supplied by Microsoft (which is apparently the latest driver - Version 18.104.22.168 dated 26/3/09 and digitally signed by Microsoft). I loaded Win7 onto my Lenovo with the 4965AGN and my Fiancé's which is a Dell running a 5100AGN wireless NIC (these are both N Class). Her laptop can see my N class router (Billion 7404VNPX) but mine can't. I could see 15 other WAP's in the block of units I live in, but not my own. I tried dropping my router back to B&G only, but still couldn't see it. I also have a G class router (Billion 6404VGP) which is acting as a wireless relay for my primary router and my PC couldn't see it either. After seeing your post, I remembered that both of my routers were running on channel 13, so last night dropped my channel to 1 and then 11, and my PC saw the router immediately once I got off channel 13.
I know this doesn't help you, but thanks heaps for putting the post up here, or I still wouldn't have wireless access today - and maybe Intel/Microsoft can do something about the release of incomplete drivers such as this in the future?!? :-\
I spent a couple of days working through the same issue with the same Intel wireless solution. After much experimentation I finally have it running well by rolling back the adapter driver to 22.214.171.124 - not sure where you can get this driver, it was an old on that was already on my system. The driver is from 2007.
Nevermind - worked for two days and died again - even got a BSOD this time