I've an HP dm4t laptop with an Intel Centrino Wireless 1000 card. Everything was working fine on Natty but when I upgraded to Oneiric, the wireless (specifically connectin to WPA2 Personal) stopped working - I would enter the password and it would try to connect but fail.
Since then, I've tried everything including a complete reinstall of the system (along with reformatting the hard drive) to no avail. Oddly enough though, when I run the installation procedure and it asks me to connect to the internet, the wireless works fine. It also doesn't seem to be a kernel issue as I installed Natty with the newest 3.x kernel and the wireless worked fine.
PS - I have only tested with WPA2 since that's all that I've available but it's possible the wireless would work ok with other types of networks.